As President Trump this weekend opened what could become a global trade war, a growing number of countries, including America’s closest allies, are forging their own economic partnerships without the United States. If Washington is putting up a higher fence around its trade, other nations are lowering theirs.

In just the last two months, the European Union concluded three new trade deals.

The bloc, completing negotiations that started 25 years ago, reached a major agreement with four South American countries in December to create one of the world’s largest trade zones, linking markets with 850 million people.

Two weeks later, the European Union struck a deal with Switzerland. Then last month, the bloc bolstered trade arrangements with Mexico. It also resumed talks, after a 13-year postponement, on a free-trade agreement with Malaysia.

“With Europe, what you see is what you get,” the European Commission president, Ursula Von der Leyen, boasted to the World Economic Forum in Davos, Switzerland. “We play by the rules. Our deals have no hidden strings attached.”

On Saturday, Mr. Trump ordered 25 percent tariffs on Mexico and Canada — partners in a trade bloc that he himself signed in his first term — and 10 percent tariffs on China. By late Monday, the tariffs on Mexico and Canada had been delayed a month, but Europe, Mr. Trump promised, was next.

Of course, the United States, with the planet’s largest and strongest economy, cannot be ignored. But it can, at least sometimes, be avoided.