Trump wondered aloud at the Oct. 9 meeting: How do we keep this going? McConnell, R-Ky., replied that there was only one person who could do it: the president himself.
Since that conversation, which was confirmed by three people with knowledge of the session, Trump has held a series of rallies in Senate battleground states - with plans for at least 10 in the final six days of the campaign up and down the ballot - and Republicans have grown increasingly confident about their prospects in the Nov. 6 midterm elections.
McConnell has been telling associates that Republicans are in a strong position to hold the Senate and could pad their narrow 51-to-49 advantage by a couple of seats, according to people familiar with the talks, though the Kentuckian avoids precise predictions.
The optimism marks a shift from early September, when officials were fretting over struggling candidates and contemplating the possibility of losing both chambers of Congress.
Although Republicans still feel like underdogs to hold the House amid anger with Trump, especially in the suburbs, they believe they have energized enough voters in Trump-friendly regions to keep the Senate, thanks to an uptick in the president's popularity and GOP outrage with Democratic efforts to prevent the confirmation of Kavanaugh, who was accused of sexual misconduct.
"It looked pretty bad a few weeks ago, but I think it's looking better for us," said Sen. Orrin Hatch, R-Utah.
Republicans say they are well positioned to pick up a seat in North Dakota and are closing in on another one in Missouri, where polls show a close race. But struggles in the Upper Midwest and fresh worries about Florida have raised questions about how many more they can add.
GOP strategists also think they have gained the advantage in Texas and Tennessee, two states that caused nervousness earlier this year. Nevada and Arizona, which they are also defending, are still vulnerable but are winnable, they said.
The president's political team is trying to remain flexible on his schedule for as long as possible to allow polling, early voting and other emerging data to identify the Senate, House and governors' races where he can maximize his impact, according to a person familiar with his political strategy, who, like others interviewed for this article, spoke on the condition of anonymity to describe private deliberations.
The GOP is protecting the Senate majority on friendly turf. Democrats are defending 26 seats, including 10 in states Trump won in 2016. The GOP is defending only nine.
"These are not red states, these are not Republican states. These are Trump states," said White House political director Bill Stepien, noting that some have been closely contested in previous presidential elections.
Led by Trump, Republicans have sought to use the Kavanaugh nomination and the caravan of migrants headed toward the U.S.-Mexico border to energize their base in many of these states, while casting Democrats as angry extremists who are soft on immigration.
Democrats have been singularly focused on health care, slamming Republicans for trying to undo the Affordable Care Act and putting protections for Americans with preexisting medical conditions at risk.
Both parties have flooded the airwaves with cash. They have invested about $173 million for Senate commercials in the final two weeks of the campaign, according to estimates from people tracking ad buys, with Democrats accounting for a significant portion of the money.
Democrats are tempering expectations, acknowledging they are unlikely to hold North Dakota but hopeful about the toss-up races elsewhere breaking their way.
"If there is a big wave we could take back the Senate, if there is no wave we could lose seats with this tough map, and if there is a medium size wave we'll be close to where we are now," Senate Minority Leader Charles Schumer, N.Y., said in a statement.
In North Dakota, Democratic Sen. Heidi Heitkamp's campaign has struggled for months to compete with Republican Rep. Kevin Cramer. Her odds appeared even longer after she apologized this month for an ad that included names of victims of domestic violence, sexual assault or rape without their permission.
Still, Heitkamp, who voted against Kavanaugh, raised $12.4 million during the first 17 days of October, according to federal financial records, a massive sum for a Senate candidate.
In Missouri, Sen. Claire McCaskill, D, and state Attorney General Josh Hawley, R, have been locked in a close and contentious contest in which Hawley has underscored his support for Kavanaugh and McCaskill has decried his role in a lawsuit targeting the health-care law and its preexisting-conditions protection.
Sen. Joe Donnelly, D-Ind., has been another a top target of Republicans, who have sought to cast him as liberal. A new U.S. Chamber of Commerce ad shows his photo with pictures of Sens. Bernie Sanders, I-Vt., and Elizabeth Warren, D-Mass.
Donnelly has fought back, recently airing an ad saying he opposes calls to abolish Immigration and Customs Enforcement and supports funding Trump's border wall.
Increasingly diverse Florida has proven to be a challenge for Republicans. Gov. Rick Scott, R, has kept his distance from Trump as he seeks to unseat Sen. Bill Nelson, D, whose campaign got off to a sluggish start. Some top Republicans are privately worried that Nelson will prevail, particularly since Tallahassee Mayor Andrew Gillum, D, leads in polls over former Rep. Ron DeSantis, R, in the governor's race.
"Governor Scott is in an extremely precarious spot because his fate could be determined by the governor's race: momentum for Gillum or a wayward comment by DeSantis," said Dan Eberhart, a fundraiser for Scott and DeSantis.
Scott has pumped more than $12 million of his own money into the campaign this month, federal financial records show, with a total personal investment of some $51 million.
Other states have been even bigger disappointments for the GOP, which once envisioned a Senate supermajority of 60 votes.
In Ohio, Wisconsin and Pennsylvania - all states Trump won - Democratic incumbents are heavily favored to win reelection. In West Virginia, a state Trump won by 42 percentage points, GOP leaders are not optimistic about defeating Sen. Joe Manchin III. Manchin was the only Democrat to vote for Kavanaugh's confirmation.
"Where the map started versus where it is today is fundamentally different," said Lauren Passalacqua, communications director for the Democratic Senatorial Campaign Committee.
For much of the year, Democrats have put pressure on Republicans in Texas and Tennessee. Rep. Beto O'Rourke, D-Texas, has raised record cash and attracted large crowds. Well-known former governor Phil Bredesen, D, has used his personal fortune to make a centrist pitch in Tennessee and held an early lead in polls.
But GOP leaders believe Sen. Ted Cruz, R-Texas, and Rep. Marsha Blackburn, R-Tenn., have improved their positions in the past few weeks and are in good shape to keep their states in Republican hands.
Republicans are less comfortable in Nevada, where Dean Heller is the only Republican senator running for reelection in a state Hillary Clinton won. Heller has embraced Trump in his bid to defeat Rep. Jacky Rosen. "Everything you touch turns to gold," the onetime Trump critic told the president at a recent campaign event.
Trump's fondness of using nicknames to attack his opponents in the 2016 election has been evident in Nevada and elsewhere. He called Rosen "Wacky Jacky" at the rally and has disparaged Donnelly as "Sleepin' Joe."
A couple of other contests have attracted spending from outside groups in recent weeks. In Montana, Republicans haven't given up on unseating Democratic Sen. Jon Tester, though public polls have shown him leading.
In New Jersey, a national Democratic super PAC has spent money defending Sen. Robert Menendez, D, who avoided conviction in a federal corruption trial last year. He is favored to win reelection.
While confidence in holding the Senate is up at both ends of Pennsylvania Avenue, there is a recognition in the party that this election could be hard to predict. Two years ago, Democrats thought they were on the cusp of retaking the Senate majority and keeping the White House, only to suffer crushing defeats on both fronts.
McConnell has told his associates about how Schumer called him before the 2016 election to say he hoped they would have a good working relationship with the New York Democrat as Senate leader.
After the election, McConnell called Schumer back. Yes, McConnell said, he did hope the two would have a good working relationship.