It is not just the phone calls, which feature the president doing most of the talking. Lawmakers say Mr. Trump understands the value of political niceties, such as an unexpected compliment or an invitation to a White House dinner, followed by a tour of the Lincoln bedroom.
“He’s very comfortable doing that,” said Senator James Lankford, Republican of Oklahoma, who still vividly remembers a simple missive from Mr. Trump about a statement the senator made. “He wrote a note on the actual article itself — he had torn it out of the newspaper — and wrote to me saying, ‘This is a really good quote,’ signed it, and it just showed up in my office at some point in our interoffice mail.”
Lawmakers say the president’s frequent calls offer some members of Congress a new status symbol, giving them the ability to act as beleaguered recipients of constant messages from a chief executive who can’t make a move without their wisdom. The phone connection also lets them share any disagreements with the president in private, without the danger of a public blowup, which can prompt a Twitter strike from Mr. Trump.
“He is going to talk about his positions, and I’m going to talk about my positions, but I think it is important to have that level of communication,” said Senator Cory Gardner, a Colorado Republican who talks frequently on the phone with the president.
Mr. McConnell regularly recommends that Republicans who have a beef with Mr. Trump just get on the phone and speak to him.
“The thing about this president — Mitch reminds us of it all the time — this president takes phone calls from senators, Republicans and Democrats,” said Senator Kevin Cramer, Republican of North Dakota, who is a close ally of the president. “This is what makes him different from the previous president. He takes phone calls and talks to members individually.”
The ready availability can also have its drawbacks. Mr. Cramer recalls being on Air Force One with the president last year when Mr. Trump returned a call he believed was from Senator Robert Menendez, Democrat of New Jersey, who had recently been acquitted of corruption charges. The president congratulated him and suggested that Mr. Menendez had been treated unfairly. It turned out to be a prank call from a radio host, but the embarrassing episode did not diminish the president’s enthusiasm for working the phones.
“You always know it is the president of the United States on the other end of the line,” said Mr. Cole, the Oklahoma congressman, explaining one of the reasons that he is always ready to take the call. “It is somebody who has 95 percent approval from my primary voters.”