May Day this year presented a starkly divided picture, with labour movements across the globe confronting vastly different responses from authorities and exhibiting sharply varied levels of mobilisation. The most significant development was not a single event but the broader pattern of state co-optation in Iran contrasting with police crackdowns in Canada and Switzerland, and a notably weakened showing by traditional union power in Argentina. Viewed from Tehran, the Islamic Republic’s official machinery moved swiftly to claim the day.

President Masoud Pezeshkian, who once served on a parliamentary labour faction, issued a lengthy message of gratitude to workers, a gesture echoed by Mohammad Eslami, head of the Atomic Energy Organisation, who extended congratulations to both workers and teachers. These state-sanctioned tributes stood in sharp relief to the confrontations unfolding elsewhere. In Montreal, thousands of demonstrators marched on Saturday, denouncing what organisers described as the government’s “attacks” on union rights, particularly a recent law restricting the right to strike.

The protest, which drew unions, community groups and students, ended with at least thirteen arrests after a separate Friday evening march turned contentious. Police in Toronto, meanwhile, laid fresh hate-crime charges against six individuals for rioting at a pro-Israel event last November, underscoring the volatile intersection of labour protest and political polarisation. In a separate incident, officers are searching for a suspect who fired an Orbeez-style replica gun at visibly Jewish victims in what is being treated as a hate-motivated assault.

Across the Atlantic, Swiss authorities braced for unrest in Geneva, where anti-G7 groups threatened to disrupt May Day festivities with what police described as “muscled” tactics. Analysts in London note that the convergence of anticapitalist, pro-Palestinian and feminist causes has made the traditional labour parade a flashpoint for broader grievances. In Buenos Aires, the picture was one of union decline.

A mobilisation by the CGT on the eve of May Day drew a sparse crowd, offering relief to the government of Javier Milei, which faces mounting criticism over its labour policies. One union leader promised a “much stronger” strike, yet the muted turnout signals that organised labour is struggling to rally public anger. As the political centre of gravity shifts rightwards in Argentina and Canada, and security forces adopt increasingly stringent tactics, the future of May Day as a barometer of working-class power appears uncertain.

What remains clear is that the day has become a mirror for each country’s political fault lines, and those are deepening.