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John Baez (Dec 10 2025 at 15:54):This could be a reason not to hold conferences (like ACT) in the United States. From the Washington Post:
U.S. plans to ask visitors to disclose 5 years of social media history
The proposal would affect travelers from countries on the visa waiver program, including Australia, Britain, France, Germany, Israel, Japan and South Korea.
The United States could begin requiring visitors from countries on the visa waiver program to provide up to five years of their social media history, according to a U.S. Customs and Border Protection proposal posted to the Federal Register to be officially published Wednesday.
There are dozens of countries on the visa waiver program list, including many European nations, Australia, New Zealand, South Korea, Japan, Brunei, Singapore, Qatar, Israel and Chile.
The proposal suggests adding social media as a “mandatory data element” for an Electronic System for Travel Authorization (ESTA) application.
Applicants would also have to provide additional information “when feasible,” according to the proposal. The list includes telephone numbers used in the last five years, email addresses used in the last 10 years, IP addresses and metadata from electronically submitted photos, and biometrics, including facial, fingerprint, DNA and iris data.
It would also require applicants to provide information about their family members, including names, telephone numbers, dates of birth, places of birth and residences.
According to CBP, the proposal is open for a 60-day public comment period.
John Baez (Jan 11 2026 at 17:09):Is anyone here aware of efforts to move the ICM so that it doesn't take place in the US? Currently the International Congress of Mathematicians (ICM) is going to be held in Philadelphia, 23–30 July 2026. You'll recall that when Russia invaded Ukraine, the 2022 ICM was moved out of St. Petersburg after some heel dragging.
All I've seen about this is Peter Woit's column where he wrote:
In 2022 the St. Petersburg ICM was canceled due to the Russian military entering Ukraine and attempting to take over the country by force. The US has threatened to do the same thing to Greenland and to Panama. Will the Philadelphia ICM be canceled if this happens?
Morgan Rogers (he/him) (Jan 12 2026 at 09:11):Depends whom and where the organisers are, no doubt.
Cole Comfort (Jan 12 2026 at 14:07):Morgan Rogers (he/him) said:
Depends whom and where the organisers are, no doubt.
I would imagine that in general there are more influential people in the American sphere of influence, rather than the Russian sphere of influence. If you recall, LiCS was in Israel not too long ago, and there was not much pushback at all.
John Baez (Jan 13 2026 at 04:18):It may also depend on whether the US invades Greenland before July 23rd.
John Baez (Jan 26 2026 at 22:22):The French Mathematical Society is not coming to the International Conference of Mathematician in Philadelphia in 2026:
La SMF ne tiendra pas de stand au Congrès International des Mathématiciens (ICM) de Philadelphie en 2026.
(Motion du Conseil d'Administration du 16 janvier 2026)
En effet ni la délivrance de visas par le pays hôte, ni sa sécurité intérieure alors qu'y est régulièrement évoquée la loi martiale, ne semblent garanties.
Par ailleurs la SMF reste fondamentalement attachée à l'héritage de Benjamin Franklin, inséparable de la pensée rationnelle, et condamne la défiance envers la science et toute atteinte aux libertés académiques.
John Baez (Jan 26 2026 at 22:23):Or for those of us who can barely read French:
The French Mathematical Society (SMF) will not have a booth at the International Congress of Mathematicians (ICM) in Philadelphia in 2026.
(Motion of the Board of Directors, January 16, 2026)
Indeed, neither the issuance of visas by the host country nor its internal security, given the frequent discussions of martial law, seem guaranteed. Furthermore, the SMF remains fundamentally committed to the legacy of Benjamin Franklin, which is inseparable from rational thought, and condemns the distrust of science and any infringement on academic freedom.
John Baez (Feb 10 2026 at 06:50):If I understand this correctly, it might reduce attendance at all conferences in the US:
Yesterday the Trump Administration announced a proposed big change in policy for people traveling to the US under the Visa Waiver Program. I believe the Visa Waiver Program covers people traveling to the US for short-term business (B-1) or tourism (B-2) from certain countries.
The new change would affect ESTA, an automated system that determines the eligibility of visitors to travel to the US under that program:
https://www.govinfo.gov/content/pkg/FR-2025-12-10/pdf/2025-22461.pdf
If the proposed changes are adopted after the 60-day consultation, then people traveling to the U.S. will be forced to use a U.S. government mobile phone app, submit their social media from the last five years, and submit email addresses used in the last ten years, including of family members. They’re also proposing the collection of DNA.
More details here:
Kevin Carlson (Feb 10 2026 at 17:40):I believe this was actually announced December 10, so the comment period is over. Perhaps the Privacy International post was new yesterday as the comment period was ending? I can’t open it now, site seems to be down, but I don’t see any other new reports indicating any update. I hope they got a lot of convincing comments.
John Baez (Feb 10 2026 at 20:49):Yes, the Privacy International post showed up yesterday right when the comment period ended. Sorry not to make that clear.
I guess we'll have to wait to hear news about whether this policy actually gets implemented. It will be somewhat difficult to implement, though I suppose the government can implement it selectively and use it to punish anyone they want - by checking to see if that person gave them every email address they used in the last 10 years, and all social media posts from the last 5 years.
Kevin Carlson (Feb 11 2026 at 00:14):Ah, yeah, I think saying Trump announced it yesterday made it sound like you were reading the comment period as having just begun.
Well, implementing it, in the sense of telling everyone they have to include this information, would be easy and would probably cause pretty notable damage to international tourism and business travel, even if they hardly ever try to actually enforce it. It does seem it would be impossible to find all the email addresses and socials anybody used over x time, but it's hard to know exactly which of those things the government might have in their files. I saw in some other link some official claiming that all they'd be asking for was social media handles, to check against intelligence files, rather than demanding visitors make their social media profiles public for CBP's perusal upon entry, which I think they've been either floating or actually implemented for student visas.
Eric Dolores (Mar 17 2026 at 00:13):Letter to the editor with title "Grave Concern About ICM in USA in 2026" at the Notices of the AMS by Hendrik De Bie https://www.ams.org/journals/notices/202604/202604FullIssue-optimized.pdf
John Baez (Mar 17 2026 at 00:14):Thanks! This letter by Hendrik De Bie on page 275 is somewhat overshadowed by a letter with the opposite viewpoint written on behalf of the ICM organizing committee and the collection of articles "The ICM Comes to the United States: Philadelphia, July 23–30, 2026" on page 295, which includes Jalal Shatah's article "A War Refugee as ICM2026 Chair", clearly designed to defuse this issue.
By the way, there's a petition asking the ICM to move its 2026 meeting out of the US, here:
https://docs.google.com/forms/d/e/1FAIpQLSdHJhc8X83b8oL6rH2KDX0I730eraum5I8_IlWY23F82mHuag/viewform
David Michael Roberts (Mar 17 2026 at 00:23):Were there statements like
Gathering in St Petersburg is not only an academic act, but also an affirmation that mathematics transcends political divisions and that our community will not be intimidated or divided.
before the last ICM?
John Baez (Mar 17 2026 at 00:26):I don't think it went quite that way. You can learn some of the history here.
David Michael Roberts (Mar 17 2026 at 02:33):In case it wasn't clear, the quote in my previous comment was taken verbatim from the response letter from the representative of the organising committee of this year's ICM, just with "Philadelphia" replaced by "St Petersburg".
I'm wondering if people tried to defend continuing to hold the ICM there last time in the face of rumblings of opposition, or not, what arguments they gave at the time if so, and why the argument this year to push on with the plan shouldn't be said to apply to what happened last time. If the reasons given this year apply equally well to last time, then are they really the best reasons? Since I think people agreed that last time it was a good idea to move the St Petersburg ICM to online.
David Michael Roberts (Mar 17 2026 at 02:36):The timeline of the progress as much as can be gathered from Peter W's links to dated tweets and statements is interesting, I hadn't remembered the sequence of events.
John Baez (Mar 17 2026 at 05:24):I'm wondering if people tried to defend continuing to hold the ICM there last time in the face of rumblings of opposition, or not, what arguments they gave at the time if so....
I found something the IMU wrote on February 26th, 2022, 5 days after the invasion of Ukraine. Some quotes:
We, the Executive Committee of the IMU, have analyzed the situation carefully. We strongly condemn the actions by Russia. Our deepest sympathy goes to our Ukrainian colleagues and the Ukrainian people.
Given this situation, it is impossible for the IMU to host the ICM and the GA [general assembly] as traditional in-person events in Russia. We have considered the possibility of postponing the ICM by one year, similar to what happened with the Warsaw ICM. However, it is unclear how the situation will evolve within a year, and thus this is not a feasible option. Another option discussed was to cancel the ICM completely. The IMU considered this option as unnecessarily drastic, and it would not serve the mathematical community. In this day and age, we have the option of carrying out a fully virtual ICM, following the original schedule of the ICM. Speakers can choose to submit recorded talks, or give live talks. We understand that different time zones will make this problematic for many, but an ICM has a tight program, and we see few alternatives. Participation in a virtual format will however be free of charge. As this requires substantial organizational work, we will return with further details as soon as they are available.
As for the General Assembly, we consider it of vital importance to meet in person. However, as we cannot meet in Saint Petersburg, we will find an alternative venue outside Russia for the GA.
Kevin Carlson (Mar 17 2026 at 06:15):David Michael Roberts said:
I'm wondering if people tried to defend continuing to hold the ICM there last time in the face of rumblings of opposition, or not, what arguments they gave at the time if so, and why the argument this year to push on with the plan shouldn't be said to apply to what happened last time. If the reasons given this year apply equally well to last time, then are they really the best reasons? Since I think people agreed that last time it was a good idea to move the St Petersburg ICM to online.
Woit linked to some group pushing back on the cancellation in his timeline post, but it looks like it was clear to essentially all in February 2022 that it was almost certainly going to be physically impossible for the great majority of potential attendees to get to St Petersburg, even if they were willing to take on the risk of at least flying over, and conceivably landing in, the zone of an active, large-scale conventional war complete with tanks and trenches. I think it’s possible to make a case for cancelling this ICM on the basis of the invasion of Iran and the apparent risk to attendees of being spirited off to immigration detention centers for weeks with no basis, especially attendees with a gender varying from their “sex assigned at birth”, as the current administration insists on using, but it still looks like an objectively very different situation than St. Petersburg. If they were to cancel this one, which seems not at all likely comparing the amount of uproar to date to that in 2022, it seems kind of hard to see where the next could be held but, essentially, Scandinavia.
David Michael Roberts (Mar 17 2026 at 06:54):Kevin Carlson said:
ake on the risk of at least flying over, and conceivably landing in, the zone of an active, large-scale conventional war complete with tanks and trenches.
OK, this was a difference that wasn't occurring to me. I wasn't thinking of diverted flight paths over Ukraine, that's for sure. Not sure what the risk of open combat taking place in the environs of St Petersburg were thought to be, though.
Morgan Rogers (he/him) (Mar 17 2026 at 12:34):Why Scandinavia @Kevin Carlson ?
John Baez (Mar 17 2026 at 15:25):One thing ICM attendees shouldn't do is take a side-trip to Canada or Mexico and try to reenter the US. Their US visas may not cover that, and that's how people have gotten in serious trouble:
started working in California and travelled back and forth between Canada and the US multiple times without any complications – until one day, upon returning to the US, a border officer questioned me about my initial visa denial and subsequent visa approval. He asked why I had gone to the San Diego border the second time to apply. I explained that that was where my lawyer’s offices were, and that he had wanted to accompany me to ensure there were no issues.
After a long interrogation, the officer told me it seemed “shady” and that my visa hadn’t been properly processed. He claimed I also couldn’t work for a company in the US that made use of hemp – one of the beverage ingredients.
[...]
There was no explanation, no warning. He led me to a room, took my belongings from my hands and ordered me to put my hands against the wall. A woman immediately began patting me down. The commands came rapid-fire, one after another, too fast to process.
They took my shoes and pulled out my shoelaces.
“What are you doing? What is happening?” I asked.
“You are being detained.”
“I don’t understand. What does that mean? For how long?”
“I don’t know.”
That would be the response to nearly every question I would ask over the next two weeks: “I don’t know.”
John Baez (Mar 17 2026 at 15:28):A German tattoo artist who tried to enter the United States from Mexico through the San Diego border has been in Immigration and Customs Enforcement (ICE) detention for over a month, according to a friend who witnessed her being detained.
Jessica Brösche, a Berlin-based tattoo artist, had been vacationing in Mexico when she decided to travel to the US from Tijuana with an American friend, Nikita Lofving. But at the San Ysidro port of entry immigration authorities took Brösche into custody.
John Baez (Mar 17 2026 at 15:32):There are other cases. In all the cases I know, the person was trying to cross the border into the US in a manner not explicitly allowed by their visa.
Kevin Carlson (Mar 17 2026 at 15:45):Morgan Rogers (he/him) said:
Why Scandinavia Kevin Carlson ?
I was about to say France, but I’m not really sure what situation one could rely on in Paris if the national rally were in power.
Morgan Rogers (he/him) (Mar 17 2026 at 16:15):But there are so many places in the world. The IMU has over 80 members according to their websites. Surely there are more places that could host it?
Kevin Carlson (Mar 17 2026 at 17:49):I suppose Argentina or Mexico would probably work. Thailand? I think Hyderabad and Rio are the furthest south it's ever been; Australia would be quite inconvenient. But even India is an interesting case that had come to my mind: there have been some seven substantial armed conflicts between India and Pakistan since World War II. I wonder whether one ought to argue that Hyderabad also ought to have been cancelled had there been such a conflict ongoing in 2010. Somewhat similarly, Beijing in '02 would not, I think, be easy to imagine these days.
I think it needs to be in a reasonably large, reasonably wealthy country to manage the hosting, and one for which as many countries as possible have as strong of visa requirements as possible, and also one which is politically quite stable and not currently engaged in any major international crimes, which is welcoming to people of various identities which may be discriminated against in some countries...there's really not an endless supply of such countries.
Matteo Capucci (he/him) (Mar 18 2026 at 08:47)::flag_italy: we got good wine too
John Baez (Mar 18 2026 at 17:39):On the eastern side of the world, Singapore meets all of Kevin's criteria. I lived there 2 years and spent summers there for many more, and I can assure you you won't be thrown in jail if you litter or spit gum on the sidewalk. Don't bring in illegal drugs, though.
Kevin Carlson (Mar 18 2026 at 19:06):Yes, I hadn’t listed Japan and Korea because they did it recently but Singapore’s a nice idea.
Cole Comfort (Mar 18 2026 at 21:12):Morgan Rogers (he/him) said:
But there are so many places in the world. The IMU has over 80 members according to their websites. Surely there are more places that could host it?
Vietnam is also a member
John Baez (Mar 18 2026 at 22:08):Grothendieck taught his math course while Vietnam was being bombed. He wrote:
Like most more or less public activities, the lectures were scheduled between about
6 and 10 a.m., because the bombing usually took place later in the day, rarely before
11 a.m. During most of my stay the sky was cloud-covered, and consequently there
were few bombing raids. The first serious bombardments had been anticipated; they
took place on Friday 17 November, two days before we left for the countryside. Three
times my talk was interrupted by alarms, during which we took refuge in shelters.
Each alert lasted about ten minutes. Something which is at first very striking to the
newcomer is the great calm, almost indifference, with which the population reacts
to the alarms, which have become a daily routine.
Most ICM participants would not put up with this, but luckily the USA is busy bombing some other country so Vietnam is quite peaceful.
Amar Hadzihasanovic (Mar 19 2026 at 08:23):I believe Colombia also meets all the requirements.