President Trump blamed diversity requirements at the Federal Aviation Administration and his two Democratic predecessors for the midair collision over the Potomac River on Wednesday night, saying that standards for air traffic controllers had been too lax.

Mr. Trump cited no evidence, and even admitted when pressed that the investigation had only just begun.

Moments later, he blamed the pilots of the Army helicopter that appeared to fly into a passenger jet that was on final approach to Reagan National Airport, across the river from the capital.

Mr. Trump went back and forth between blaming diversity goals that he said were created by President Barack Obama and President Joseph R. Biden Jr., and then saying that an investigation was necessary.

His instant focus on diversity reflected his instinct to immediately frame major events through his political or ideological lens, whether the facts fit or not.

It is something he has done before: After a terrorist attack in New Orleans a month ago, he blamed illegal immigration, even though the attacker was a U.S. citizen born in Texas.

When asked how he could say that diversity hiring was to blame for the crash even though basic facts about the midair collision were still being sought by investigators, he said, “Because I have common sense.”

“For some jobs, we need the highest level of genius,” he said.

Of the F.A.A. under Mr. Obama, Mr. Trump said: “They actually came out with a directive, too white.”

An audio recording of the air traffic controllers’ warnings to the helicopter just before the crash indicated that a controller first warned the helicopter to look for a Canadair Regional Jet, and then told the helicopter pilot to go behind the jet as it was landing. That exchange will be part of the investigation.

Mr. Trump appeared in the White House briefing room with Vice President JD Vance; the newly sworn-in transportation secretary, Sean Duffy; and the defense secretary, Pete Hegseth. All three men began their comments by praising Mr. Trump’s leadership and repeating that they would eliminate diversity requirements and focus on competence.

Mr. Trump named a new acting head of the Federal Aviation Administration during the news conference; none had been appointed by him until Thursday. The appointee did not speak at the news conference, nor did the head of the National Transportation Safety Board, who was also in the room.