Senator Mitch McConnell, the longtime top Senate Republican, said on Wednesday that he would give up his spot as the party’s leader at the end of this year, acknowledging that his Reaganite national security views had put him out of step with a party now headed by former President Donald J. Trump.
“Believe me, I know the politics within my party at this particular time,” Mr. McConnell, who turned 82 last week, said in a speech on the Senate floor announcing his intentions. “I have many faults. Misunderstanding politics is not one of them.”
His decision, reported earlier by The Associated Press, was not a surprise. Mr. McConnell suffered a serious fall last year and experienced some episodes where he momentarily froze in front of the media. He has also faced rising resistance within his ranks for his push to provide continued military assistance to Ukraine as well as his close-to-the-vest leadership style.
Mr. McConnell had said that he would serve out his full Senate term ending in 2026, but had been more opaque about whether he would try to remain leader after the November elections.
His announcement followed a White House meeting on Tuesday where he strongly advocated congressional passage of a foreign aid bill that includes more than $60 billion in aid for Ukraine and urged Speaker Mike Johnson to put the proposal on the House floor.
“I believe more strongly than ever that America’s global leadership is essential to preserving the shining city on a hill that Ronald Reagan discussed,” Mr. McConnell said.
Representative Hakeem Jeffries of New York, the Democratic leader, said he anticipated that Mr. McConnell’s decision to step down would free him to push aggressively for the Ukraine aid.
“It is probably the case that on his way toward retirement, he’s going to work as hard as he can to make sure that the national security bill gets over the finish line in the House and the Senate to President Biden’s desk,” Mr. Jeffries said in an interview.
Mr. McConnell became the longest serving Senate leader in history at the start of this Congress, surpassing Mike Mansfield of Montana and fulfilling a personal goal. Though he worked closely with Mr. Trump in placing conservative judges on the federal bench and three justices on the Supreme Court, Mr. McConnell broke with Mr. Trump over his refusal to acknowledge that President Biden had won the 2020 election and over the Jan. 6, 2021, assault on the Capitol, which Mr. McConnell blamed on Mr. Trump even though he voted against convicting him on impeachment grounds.
In his remarks, Mr. McConnell also said the recent death of a close relative had given him pause for reflection.
“When you lose a loved one, particularly at a young age, there’s a certain introspection that accompanies the grieving process,” he said. “Perhaps it is God’s way of reminding you of your own life’s journey to prioritize the impact of the world that we will all inevitably leave behind.”