In an interview on Tuesday, Mr. Rubio said that since his presidential campaign ended in March 2016, he has spent a lot of time contemplating what Mr. Trump got right and what he misjudged. And while Mr. Rubio insisted he had no plans to run for president again — “It’s so far-off in the future, I don’t know where my mind will be” — he said he believed that the conservative movement’s tenets need to evolve beyond sterile economic arguments of low taxes and high economic growth.
“I think the challenge is how the policies that come from those principles, by necessity, have to look different in the 21st century than they did in 1980 or 1985,” Mr. Rubio said. “America is not an economy. It’s a country,” he added, channeling some of Mr. Trump’s populism. “And we have a bigger job than just to increase G.D.P.”
Mr. Needham said he agreed with that diagnosis.
“Any fair-minded observer of the last several years would say conservatives have work to do in order to assure our principles remain relevant,” Mr. Needham said in an interview. “There was truth in candidate Trump’s declaration that this is the Republican Party, not the Conservative Party. Our challenge as conservatives is to build a movement that inspires a majority coalition of Americans.”
But beyond their shared views on the party’s need to have a better 20-year plan, the two have taken very distinct approaches to leadership. Mr. Needham has been a leading practitioner of the uncompromising, scorched-earth style of political combat that was a trademark of Tea Party-inspired politicians and activists. He frequently clashed with the Republican leadership in Congress and challenged it to drive a harder bargain on issues like defunding the Affordable Care Act, which led to a two-week government shutdown in 2013 that most Republicans came to see as ill advised.
Mr. Rubio, who professed to be one of those shutdown-wary Republicans even though he voted against several bills that would have kept the government open, has been more accommodating in his dealings as a senator. He has worked with Democrats like Senator Chuck Schumer of New York, the minority leader, on immigration reform. And he remains close to his party’s Senate leaders. His bid for president had the backing of some of the Republican Party’s most establishment-friendly — and anti-Trump — donors.
Mr. Needham and Mr. Rubio have often had very different things to say about Mr. Trump. Given his anti-establishment sensibilities, Mr. Needham has largely lauded the president’s agenda of low taxes and a hard-line posture toward China. He has praised Mr. Trump for helping the Republican Party forge a stronger bond with Americans who feel socially and economically disconnected and who are eager to shine a light on the corruption and cronyism they believe is rampant in Washington.
Mr. Rubio, who has been running for office more or less since he was a West Miami city commissioner in his 20s, clashed bitterly and personally with Mr. Trump during the 2016 campaign. He denounced Mr. Trump as someone who operated from the same playbook as “third-world strongmen” who ruled Latin America. He said Mr. Trump had preyed on vulnerable students by selling them worthless degrees from Trump University. In one of the more memorable but desperate moments of Mr. Rubio’s campaign, he also ridiculed Mr. Trump’s tendency to misspell things on Twitter and suggested he once wet his pants at a debate.
Lately, however, Mr. Rubio has done what many other Republicans have done and tried to work with the president on the parts of his agenda that they do not find objectionable. He won concessions from the White House to make the child tax credit more generous in last year’s tax overhaul.
The senator has also been generally supportive of the president’s efforts to punish China for what they say is its disadvantaging of American products and causing of job losses with unfair trade practices.
Mr. Needham and Mr. Rubio both agree there is a need now to work with the president as much as possible while also looking beyond him to plan for what the party and the country look like once he is gone.
“As someone who’s lived his career in the movement, the challenge is preserving the principles that Reagan fought for while also being able to refresh that pool of ideas to keep pace with our times,” Mr. Needham said. “That’s a bigger effort than any one president or any one person.”
Mr. Rubio’s chief of staff position has been vacant since January, when he fired the previous occupant of the job after allegations of inappropriate conduct surfaced.