Few Republicans in Washington are willing to go head-to-head with President Trump Donald John TrumpBubba Wallace to be driver of Michael Jordan, Denny Hamlin NASCAR team Graham: GOP will confirm Trump's Supreme Court nominee before the election Southwest Airlines, unions call for six-month extension of government aid MORE, but there is one band of GOP members willing to stand up to the leader of their own party: lawmakers who have announced their retirements.

While it’s not uncommon for members to feel far more liberated on their way out the door, it has taken on a whole new meaning in the Trump era, where lawmakers are confronted daily by a never-ending stream of White House controversies.

The GOP’s retirement caucus has provided some of the most biting commentary on the president in recent months, with Rep. Ryan Costello Ryan Anthony CostellloTrump struggles to stay on script, frustrating GOP again Bottom line Former GOP Rep. Costello launches lobbying shop MORE (Pa.) — the latest Republican to jump ship from Congress — even saying that his frustrations with the Trump administration helped drive him to the exit.

ADVERTISEMENT "I always thought I was freewheeling, but I think I've become a little bit more freewheeling," Costello told The Hill, discussing how his attitude has already shifted in the nearly two weeks since he announced his retirement. "It's a little bit less stressful."

There has been a wave of GOP retirements over the last several months as Republican members brace for tough midterm elections this November. About two dozen House Republicans are retiring outright, while four GOP senators have decided to call it quits.

Members have cited a mix of reasons for deciding to leave Congress, from expiring chairmanship terms to family and personal reasons.

But some lawmakers have pointed to another factor: Trump. They say that the unconventional president has added new headaches to an already demanding job.

“It’s exhausting,” centrist Rep. Charlie Dent Charles (Charlie) Wieder DentRepublican former Michigan governor says he's voting for Biden Biden picks up endorsements from nearly 100 Republicans Bush endorsing Biden? Don't hold your breath MORE (R-Pa.), who announced his retirement last fall, told The Hill. “What we’ve gotten out of the administration is all this disruption, and it’s very destabilizing.”

Dent has become one of the most vocal and outspoken Trump critics in Congress, always offering up a reliable soundbite to reporters in the Capitol seeking GOP reaction to the latest White House controversy.

Just last week, Dent told The Associated Press that Trump’s "lack of impulse control" is cause for concern after a week of unpredictable moves by the White House left lawmakers uneasy about key Republican agenda items.

“The spontaneity and lack of impulse control are areas of concern for lots of members on both sides of the aisle,” Dent said. “Disorder, chaos, instability, uncertainty, intemperate statements are not conservative virtues in my opinion.”

Dent first began criticizing Trump during the 2016 presidential race. He conducted polling to see how it might impact his own race and found that 4 percent of his constituents would vote against Dent for the criticism but that 4 percent would actually support him because of it.

After realizing that his attacks on Trump were largely a nonfactor in his race, Dent felt liberated — a trend that continued well after he announced his retirement in September.

But Dent said he has grown increasingly frustrated that his criticisms of Trump don’t seem to earn him points with either side of the aisle: Conservatives say he is betraying the party, while liberals say Dent’s condemnation doesn’t go far enough.

“Too many people on both sides want you to set yourself on fire for them, and when you do, they complain the temperature of the flame isn’t hot enough,” he said. “That gets old.”

Costello, whose reelection in Pennsylvania would have been more challenging due to court-ordered redistricting, has also consistently shown a willingness to needle the president on certain issues — no doubt a reflection of his moderate district.

But since his retirement announcement last week, Costello has unloaded on Trump in a series of interviews in the media, saying he believes Trump had an extramarital affair with adult-film actress Stormy Daniels and criticizing the president for threatening to veto a government spending bill.

“I think she is,” Costello replied after MSNBC’s Katy Tur asked if he believed Daniels, whose real name is Stephanie Clifford, is telling the truth.

“Whether it’s Stormy Daniels, or passing an omnibus spending bill that the president threatens to veto after promising to sign, it’s very difficult to move forward in a constructive way today,” Costello told the Daily Local News. Costello said he no longer feels obligated to respond to every single Trump tweet or White House scandal — something that had been a source of frustration for him prior to his retirement announcement. Costello said he no longer feels obligated to respond to every single Trump tweet or White House scandal — something that had been a source of frustration for him prior to his retirement announcement. "If I have something insightful to say, I'll say it. But I don't need to," he told The Hill.

Rep. Ileana Ros-Lehtinen Ileana Carmen Ros-Lehtinen'Trump show' convention sparks little interest on K Street Shalala to face Salazar in Florida rematch TechNet hires Hispanic communications director MORE (R-Fla.), who announced nearly a year ago that she would not seek reelection, has never been afraid to speak her mind.

But in recent months, Ros-Lehtinen has become one of just three Republicans to call on Environmental Protection Agency (EPA) Administrator Scott Pruitt Edward (Scott) Scott PruittJuan Williams: Swamp creature at the White House Science protections must be enforceable Conspicuous by their absence from the Republican Convention MORE to resign; she has pressed the administration to reconsider adding a citizenship question to the 2020 census; and she slammed Trump’s reported comments calling Haiti, El Salvador and African nations “shithole countries," calling the remarks “reprehensible” and “racist.”

It’s not just moderate lawmakers who have challenged the White House since announcing their exit from Congress.

Rep. Trey Gowdy Harold (Trey) Watson GowdySunday shows preview: Election integrity dominates as Nov. 3 nears Tim Scott invokes Breonna Taylor, George Floyd in Trump convention speech Sunday shows preview: Republicans gear up for national convention, USPS debate continues in Washington MORE (R-S.C.), chairman of the House Oversight and Government Reform Committee, has turned some heads in Washington with his pointed comments aimed at Trump.

Gowdy, a fierce critic of former Secretary of State Hillary Clinton Hillary Diane Rodham ClintonJoe Biden looks to expand election battleground into Trump country Biden leads Trump by 12 points among Catholic voters: poll The Hill's Campaign Report: Biden goes on offense MORE who is leading an investigation into alleged bias at the FBI and Justice Department, recently tweaked Trump publicly over the federal investigation into his campaign and Russian election meddling, telling him, “When you are innocent, act like it.”

The conservative hard-liner, who announced his retirement in January, has been one of his party’s louder defenders of special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE this year and has called Trump’s attacks on the Justice Department “not helpful.” Gowdy also broke with the assessment from Republicans on the House Intelligence Committee that there wasn’t enough evidence to prove Russian President Vladimir Putin preferred Trump during the 2016 presidential race.

Gowdy has also begun probing Pruitt’s $50-a-night housing arrangement on Capitol Hill, a GOP source told The Hill on Friday night.

Across the Capitol, retiring Sens. Bob Corker Robert (Bob) Phillips CorkerHas Congress captured Russia policy? Tennessee primary battle turns nasty for Republicans Cheney clashes with Trump MORE (R-Tenn.) and Jeff Flake Jeffrey (Jeff) Lane FlakeJeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Republican former Michigan governor says he's voting for Biden Maybe they just don't like cowboys: The president is successful, some just don't like his style MORE (R-Ariz.) have been some of the biggest thorns in Trump’s side. There have also been some nonretiring lawmakers like Sen. Lindsey Graham Lindsey Olin GrahamGraham: GOP will confirm Trump's Supreme Court nominee before the election Fox's Napolitano: Supreme Court confirmation hearings will be 'World War III of political battles' Grassley, Ernst pledge to 'evaluate' Trump's Supreme Court nominee MORE (R-S.C.) who have panned Trump, though Graham is not up for reelection this year.

Flake, long a frequent Trump critic, delivered one of his most blistering Senate floor speeches when he announced his retirement, torching members of his own party and loudly denouncing the Trump administration.

"Reckless, outrageous and undignified behavior has become excused as telling it like it is when it is actually just reckless, outrageous and undignified," Flake said. "And when such behavior emanates from the top of our government, it is something else. It is dangerous to a democracy."

That same uninhibited attitude was on full display this year at the Washington Press Club Foundation’s annual congressional dinner, where Ros-Lehtinen took the stage, though her remarks struck a much lighter tone.

“I’ve always spoken my mind whether I was running for re-election or not, but retirement did free me up to do the Washington Press Club Foundation speech, where some said I was actually funny!” Ros-Lehtinen told The Hill in an email. “However, it was a one night only show and I won’t be trying my luck at that again.”

The Florida lawmaker took several jabs at Trump and her congressional colleagues during the dinner.

“I know what the problem is: We really haven’t seen the long-form birth certificate of [Trump's] hair piece. That would put you all at ease,” she said.

Ros-Lehtinen went on to say the Trump campaign was shocked to learn that they actually won the 2016 presidential election.

And Ros-Lehtinen also joked that she was going to help write a book about dealing with the “orange monster underneath my bed.”

After Ros-Lehtinen finished her remarks, CNN’s Dana Bash quipped, “Whoever decided to pick somebody that is retiring, good call.”