McConnell and Paul themselves have spoken about the issue with increasingly regularity in recent weeks, according to people familiar with their conversations. And last month, one of the top lieutenants charged with protecting the Senate Republican majority called Doug Stafford, the chief strategist for Paul’s presidential campaign, to the headquarters of the National Republican Senatorial Committee for a one-on-one meeting.

There, Ward Baker, a blunt-spoken former Marine and the NRSC’s executive director, told Stafford that Paul’s dual campaigns were coming with a cost. Baker laid out recent polling the NRSC had commissioned on Paul’s standing in his home state and the results were bleak, according to multiple Republicans briefed on the survey. Baker told him that it was time for Paul, whose presidential campaign has dipped in the polls and flat-lined at fundraising, to refocus on his reelection.

The meeting, confirmed to POLITICO by three people briefed on the conversation, represented a key moment in the quiet push to get Paul and his team to realize that, come next summer, the junior senator from Kentucky is far more likely to be campaigning for reelection in Louisville than crowned as the GOP nominee in Cleveland.

“We don’t have unlimited patience,” said a top Senate Republican operative of Paul’s presidential candidacy.