Senate Republican leader Mitch McConnell, a longtime critic of Donald Trump and a frequent target, on Wednesday endorsed him in the 2024 presidential race.

       "It is abundantly clear that former President Trump has earned the requisite support of Republican voters to be our nominee for President of the United States," McConnell said in a statement Wednesday, just after Nikki Haley suspended her campaign.

       "It should come as no surprise that as nominee, he will have my support," McConnell added. "During his Presidency, we worked together to accomplish great things for the American people including tax reform that supercharged our economy and a generational change of our federal judiciary - most importantly, the Supreme Court."

       "I look forward to the opportunity of switching from playing defense against the terrible policies the Biden administration has pursued to a sustained offense geared towards making a real difference in improving the lives of the American people."

       In this Nov. 4, 2019 file photo then President Donald Trump, left, and Senate Majority Leader...Show more ---Show more

       Timothy D. Easley/AP, FILE

       MORE: Super Tuesday recap: Trump and Biden dominate but each see a surprising loss

       Advisers close to Trump and McConnell had been in talks for six weeks over an endorsement, sources confirmed to ABC News, as well as an overall strategy to unite Republicans to win back the Senate in November.

       The conversations between the two campaigns went through a single channel: Chris LaCivita, a top campaign adviser to Trump and Josh Holmes, a longtime political strategist to McConnell.

       In this Nov. 4, 2019 file photo Senator Mitch McConnell (R-KY) hugs President Donald Trum...Show more ---Show more

       Yuri Gripas/Reuters

       McConnell's backing comes even though he has a strained relationship with the former president. The two men have not spoken since December 2020.

       McConnell was highly critical of Trump after the Jan. 6 attack on the U.S. Capitol, calling him morally and practically responsible for the violent riot. He suggested Trump should be prosecuted for his role in what transpired.

       Meanwhile, Trump has viciously attacked McConnell over the years, calling his wife, former Trump Transportation Secretary Elaine Chao, "Coco Chao" and suggesting she was a Chinese agent.

       MORE: McConnell to step down as Senate GOP leader after nearly two decades

       Now that he is the last major GOP candidate standing, Trump is calling for unity as his campaign enters the general election phase.

       "We have a great Republican Party with tremendous talent," he said Tuesday night. "And we want to have unity and we're going to have unity and it's going to happen very quickly."

       McConnell, the longest serving Senate leader in history, recently announced he will step down from the position but made it clear he will do everything he can to win back the Senate.

       "I still have enough gas in the tank to thoroughly disappoint my critics, and I intend to do so with all the enthusiasm which they have become accustomed," McConnell said.