Secretary of State Mike Pompeo on Monday told Mitch McConnell, the Senate majority leader, that he does not plan to run for Senate in 2020, most likely ending Republicans’ hopes of securing a potentially dominant candidate for the open seat in his home state of Kansas, according to four people briefed on the meeting.
Mr. Pompeo, a former congressman from the Wichita area, has quietly explored a campaign for months. But in the aftermath of the military operation last week that killed Maj. Gen. Qassim Suleimani of Iran, Mr. Pompeo has told senior party officials that he is ruling out becoming a candidate, according to several people who have spoken with him directly.
Mr. Pompeo still has time to change his mind. The filing deadline for the primary is not until June. However, administration officials who have spoken with him in recent days said he seemed adamant about not entering the race.
Without Mr. Pompeo in the race, Republicans face an unsettled primary that includes at least one candidate, Kris Kobach, whom party leaders fear could imperil their hold on a crucial open Senate seat. Mr. Kobach, who ran unsuccessfully for governor in 2018, is popular with hard-right primary voters but widely disliked among moderate and independent voters in Kansas.
Several other candidates are competing for the Republican nomination, including Representative Roger Marshall. National Democrats have rallied behind Barbara Bollier, a state senator who left the G.O.P. to become a Democrat a little more than a year ago, as their preferred candidate.
Mr. Pompeo’s decision is a setback for Republicans working to retain their Senate majority in the November elections. Mr. McConnell aggressively courted him for months, and also deployed a number of his lieutenants to make the case that the secretary of state should return to Kansas, which he represented in the House until he joined the Trump administration.
While the state has not elected a Democrat to the Senate since 1932, Mr. McConnell and other top Republican officials are deeply worried that they could lose the seat should Mr. Kobach, the controversial former Kansas secretary of state, emerge as their nominee. An immigration hard-liner with a history of inflammatory comments, Mr. Kobach lost the governor’s race there last year.
Internal Republican polling suggested that Mr. Pompeo would have easily captured the nomination for the seat that is being vacated by Senator Pat Roberts, a longtime member of the chamber who is retiring. And for months, it seemed like Mr. Pompeo would go forward with a run as he found reasons to return to Kansas and conspicuously showed up at events in Washington that were connected to his home state.
He even appeared to win something of a blessing from President Trump after Mr. McConnell and other congressional Republicans privately emphasized to him the importance of retaining the seat.