More than 1,500 mathematicians have signed a petition to boycott the International Congress of Mathematicians this July in Philadelphia. The ICM meets every four years. It is where the Fields Medal is awarded. It is the single most important gathering in the most universal discipline humans have.
If the people who work in pure abstraction look at the United States and say “we cannot go there,” that is measurement.
The math of precedent
In 2022 the International Mathematical Union moved the ICM out of Saint Petersburg after Russia invaded Ukraine. The principle was clear: military aggression disqualifies a host country. Since that decision, the United States has started wars in Venezuela and Iran, imposed a naval blockade on Cuba (an act of war under longstanding international law), suspended visas from 75 countries, and deployed federal immigration agents across its cities. The same organizers who cancelled Russia have said nothing about America.
The paper trail is damning. In 2022 the European Mathematical Society wrote: “We call on the International Mathematical Union not to proceed with the ICM in Russia.” In 2026, the same EMS wrote that it “will continue to support the IMU and the local organizing committee.” Same institution, same structural problem, opposite conclusion.
The American Mathematical Society’s president wrote in February that the congress would “powerfully demonstrate the importance of civilizational values.” This is the language of exception. The rule applies to others. We demonstrate values.
A technically impossible defense
Defenders of the double standard argue that 2022 was different because Western sanctions made attendance in Russia literally impossible. Institutions banned travel. Flights were cancelled. Grant money could not be spent. Fair enough. But follow the logic. The West created that impossibility through its own sanctions regime. The absence of equivalent sanctions on the United States for equivalent behavior is not evidence that the situations differ. It is the double standard in its most precise form. The mechanism of enforcement is selective, not the principle.
Mein Gott, Göttingen?
When the Nazis purged Jewish mathematicians from Göttingen in 1933, they destroyed the greatest mathematics department in the world overnight. The new Education Minister asked David Hilbert how mathematics was faring without the Jews.
Mathematics in Göttingen? There is really none anymore.
The regime did not care. The talent left. America inherited it.
Now America is repelling it. The French Mathematical Society announced its boycott in January, before the wars even started. France has more Fields Medalists than any country except the United States. When France looks at the conditions on American campuses and in American cities and decides the risk is too great for its researchers, that is not posturing. France does not posture about mathematics. France is serious about mathematics.
Orders of moral magnitude
Mathematicians have a particular relationship to contradiction. You cannot do the work and tolerate inconsistency. The petition names the inconsistency directly: one invasion disqualified Russia, three conflicts do not disqualify America. That is not a political argument. It is a proof by contradiction.
The ICM has accommodated power before. Benito Mussolini was honorary president of the 1928 congress. The 1950 ICM in Cambridge nearly lost Laurent Schwartz, its Fields Medal recipient, because McCarthyism made his communist affiliations a visa problem. Alexander Grothendieck resigned from IHÉS over military funding and withdrew from professional mathematics entirely. The apartheid-era academic boycott of South Africa removed international legitimacy from a regime that craved it. The pattern is consistent. When the scientific community withdraws, it is telling you something the diplomats will not.
On MathOverflow, the question of whether to cancel or relocate the 2026 ICM has been closed four times and reopened four times. Moderators have deleted political answers to the 2026 question while the equivalent answers to the 2022 question remain untouched.
The forum cannot decide whether its own question is legitimate because answering it honestly would require applying the standard it set four years ago to the country it is in.
Deafening silence
The IMU and the Simons Foundation, which is funding the congress, both declined to comment. When the money and the organizers go quiet, they are calculating, not deliberating.
The question everyone poses is what mathematicians can do with their collective power. The answer is already visible. They do not need to achieve anything beyond what they have done.
A canary does not need a plan. It just stops singing.
The world’s best minds will not enter the country. That is not a prediction. That is the simple math.
