With three host countries (United States, Mexico, Canada) and 104 matches, the football World Cup which opens in 100 days promises to be extraordinary, in a context made uncertain by the policies of Donald Trump, the violence in Mexico and the American intervention in Iran.

Four years after the World Cup in Qatar, a tiny gas-rich emirate in the Gulf, the tournament will be one of superlatives, played in 16 venues, some as far apart as 4,000 km, across four time zones.

Between the opening match on June 11 at the Azteca Stadium in Mexico City, and the final six weeks later on July 19 in New Jersey, 48 teams, 50% more than in 2022, will compete in a global televised battle to succeed Lionel Messi's Argentina.

To give a sense of the scale of the event, the president of the International Federation of Football, Gianni Infantino, promises "104 Super Bowls" and benefits of around 11 billion dollars for the organization.

The Italian-Swiss leader, who boasts of a rare close relationship with US President Donald Trump, also estimated during an interview with CNBC the impact on the US economy, where the majority of the matches - 78 including all the matches from the quarter-finals onwards - will take place at "around 30 billion dollars in terms of tourism, catering, security, investments".

- What is the effect of Trump?

Beyond these staggering figures, the smooth running of the competition will depend on American politics, which have been particularly unpredictable since Trump's return to the White House. In the midst of celebrating the 250th anniversary of American independence, the billionaire sees this World Cup as one of the highlights of his second term.

But its customs policy, particularly against its neighbors, its threats to make Canada the 51st American state, its attacks against its European allies or its measures to limit immigration may raise questions, even if the calls to boycott the World Cup have been fairly discreet.

The US and Israeli military operation launched on Saturday against Iran, one of the qualifiers, could raise the question of the presence on American soil of the Iranian national team, which is supposed to play its three first-round matches on the West Coast.

Until very recently, the main concern was the Republican president's anti-immigrant policies, which continue to polarize Americans, and in particular the heavy-handed tactics of Immigration and Customs Enforcement (ICE). In mid-January, Washington announced a visa freeze for citizens of 75 countries, including four qualifying nations (Iran, Haiti, Senegal, and Ivory Coast), as part of the fight against illegal immigration.

Could this policy deter some foreign visitors from making the expensive trip to the United States? In addition to the seven million spectators in the stadiums, 20 to 30 million tourists are expected, according to Gianni Infantino.

- What about safety in Mexico?

In mid-February, the issue of security in Mexico arose again after the death of the head of one of the most important Mexican drug cartels in a military operation, which triggered a wave of deadly violence in several areas of the country, including Guadalajara, which is due to host four World Cup matches.

When questioned by AFP on Tuesday, Gianni Infantino said he was "very calm" about the matches taking place, and Mexican President Claudia Sheinbaum assured that there was "no risk".

Meanwhile, the main candidates to succeed the Argentinians are already in battle formation.

Besides Messi's Albiceleste, we will have to reckon with France, led by Kylian Mbappé and Ballon d'Or winner Ousmane Dembélé, who has reached the final of four of the last seven editions, the Spanish European champions, Cristiano Ronaldo's Portugal, Jude Bellingham and Harry Kane's England, as well as Brazil and Germany, perennial favorites despite inconsistent results.

But on the sporting side, not all uncertainties have been resolved, since the names of the last six qualifiers will only be known after the final playoffs at the end of March.