BRUSSELS — As diplomatic spats go, it was a spring shower in a teapot, not even a minor tempest. But European feelings were badly bruised last year when the Trump administration downgraded the diplomatic status of the European Union’s delegation to the United States without making a formal announcement or even informing the bloc about the change.

The permanent reversal of that decision was announced on Monday, with the ambassador of the European Union to the United States now again considered to be equivalent to an ambassador from a country, not just to an envoy from an international organization.

The announcement was made with some fanfare by the American ambassador to the European Union, Gordon Sondland, whom European diplomats credit with pushing hard for the fix. In a statement, Mr. Sondland called the bloc “a uniquely important organization, and one of America’s most valuable partners in ensuring global security and prosperity.”

President Trump has called the European Union “a foe” in economic competition with the United States, but Mr. Sondland said that “Europe’s security and success are inextricably linked to that of the United States, and this level of engagement and cooperation should be recognized appropriately in all settings.”