The next Congress is going to be missing some familiar faces. Thanks to a mix of retirements and defeats on Tuesday, some of the most high-profile lawmakers will soon be exiting Capitol Hill.

Some were longtime Democratic targets in the Senate that the GOP finally vanquished. Others were vocal Republican critics of President Trump who chose not to run for re-election. Others simply thought it was time to hang it up — including the speaker of the House, Paul Ryan (R-Wis.).

Here are 10 of the most notable politicians making their exit from Washington:

Sen. Claire McCaskill, D-Mo.

The Missouri senator was Republicans' white whale. She won in 2006, a good Democratic year, and six years later she drew a deeply flawed GOP challenger that helped her win re-election. But this year, Republican state Attorney General Josh Hawley finally ousted her. McCaskill was a regular on TV and Sunday talk shows and leaves as the top Democrat on the Homeland Security and Governmental Affairs Committee. McCaskill was seen as a moderate in Democratic caucus, but her votes against both of Trump's Supreme Court nominees, Neil Gorsuch and Brett Kavanaugh, helped Republicans finally sink her.

House Speaker Paul Ryan, R-Wis.

The Wisconsin Republican fashions himself a policy wonk and a budget nerd, and during his nearly two decades in Congress became chairman of both the House Budget Committee and the Ways and Means Committee. But he also found himself thrust into the national spotlight, occasionally to his chagrin.

Ryan was chosen by Mitt Romney to be his vice presidential running mate in 2012, and after their defeat Ryan became one of the de facto leaders in an increasingly divided GOP conference. After conservatives helped oust John Boehner as speaker in 2015, Ryan somewhat reluctantly accepted the job. Once Donald Trump ascended to become the GOP's presidential nominee and then to the White House, Ryan had to walk a fine line — sometimes criticizing the unconventional chief executive while also trying to find a way to work with him.

Ultimately, it may have been too much, and Ryan — along with a record number of other GOP lawmakers — seemed to see the writing on the wall that Republicans were likely to lose the House and announced his retirement in April. A close confidant of Senate Majority Leader Mitch McConnell told the New York Times that McConnell thought the move was "selfish."

Rep. Beto O'Rourke, D-Texas

The Texas congressman was first elected to the House in 2012, knocking off an incumbent congressman in the Democratic primary. Launching his bid for the Senate in March 2017, O'Rourke seemed like the longest of long shots in deep red Texas.

But his unconventional campaign took a grassroots approach. He visited all 254 counties in Texas and soon began drawing huge crowds. His rockstar-like status would soon propel him to fame beyond just Texas, as he raised an unheard of nearly $70 million for his campaign. Ultimately, O'Rourke fell just short of unseating Republican Sen. Ted Cruz — though his finish within less than three points was the best finish for a Texas Democrat statewide in decades.

O'Rourke may not be coming back to D.C. as a senator, but don't count him out of the political mix — the Beto 2020 buzz has already begun.

Sen. Heidi Heitkamp, D-N.D.

The North Dakota Democratic senator is another lawmaker Republicans had been targeting ever since she won her seat six years ago. Heitkamp was often hailed as the rare red state Democrat who could still attract rural and crossover GOP support — she narrowly won in 2012 even as Romney carried the state by almost 20 points. Trump won it four years later by an even wider 36 point margin, and he traveled repeatedly to the state to hammer her. Heitkamp often tried to bolster her moderate credentials and even sided with the president on occasion, voting for Gorsuch, his first Supreme Court nominee. But she voted against Kavanaugh after allegations of sexual assault surfaced against him earlier this year. By then, she was already seen as the most vulnerable Democratic incumbent and was likely to lose, but that vote probably sealed her fate. Some Democrats pointed out that she was down in the polls in 2012, too, and went onto win, but on Tuesday it wasn't even that close as Republican Kevin Cramer beat her by 10 points.

Sen. Jeff Flake, R-Ariz.

The Arizona senator chose to retire rather than face a primary challenge he was probably going to lose — something President Trump gloated about at his post-election press conference on Wednesday. Flake was a vocal critic of Trump from the start, and unlike other Republicans in Congress, never really wavered. He even wrote a book blasting Trump as being a fake conservative and accusing others in the GOP of making a "Faustian bargain" when accepting him. In his speech announcing his retirement, Flake decried the worsening of politics and "flagrant disregard for truth or decency" ushered in by Trump.

He's already started floating a possible primary challenge to the president in 2020.

Sen. Bob Corker, R-Tenn.

Corker wasn't an original Trump skeptic like Flake was, and for a time was even mentioned as a potential running mate or a candidate for secretary of state. But the Senate Foreign Relations Committee chairman would soon sour on Trump, becoming especially critical of his handling of foreign policy.

After one Twitter tirade of Trump's, Corker famously tweeted "It's a shame the White House has become an adult day care center. Someone obviously missed their shift this morning." Corker even flirted with deciding to run again after he had announced his retirement, but he probably would have lost that primary with now-Senator-elect Marsha Blackburn. Corker has remained a Trump critic, and the exits of both he and Flake will leave a void in the U.S. Senate.

Rep. Darrell Issa, R-Calif.

The California Republican decided to retire after nearly two decades in Congress, facing a tough re-election in a district that had voted for Hillary Clinton. (Democrat Mike Levin won his House seat in Tuesday's election). Issa gained national prominence when he became the chairman of the Oversight and Government Reform Committee after Republicans flipped the House in 2010. He wielded his gavel to investigate the Obama administration on a variety of matters, including the IRS and its treatments of conservative groups, the ATF's failed "Fast and Furious" operation and the 2012 Benghazi attacks.

Rep. Trey Gowdy, R-S.C.

The South Carolina Republican picked up the mantle from Issa, putting to use his prosecutorial background as chairman of the House Select Committee on Benghazi. Gowdy became a conservative hero for his grilling of Hillary Clinton when she testified before the committee for 11 hours. He would later assume the chairmanship of the Oversight and Government Reform Committee, as well. But Gowdy never completely toed the party line under Trump, debunking Trump's unsubstantiated claims that Democrats in the FBI had embedded a spy in his campaign. Despite his national fame, Gowdy has said he doesn't want to run for any other office or remain in political life, but simply wants to go back to being an attorney after his retirement from Congress.

Rep. Dave Brat, R-Va.

The former economics professor became a conservative icon when he notched one of the most unlikely upsets in political history by knocking off then-House Majority Leader Eric Cantor in his 2014 GOP primary. In the House, Brat joined the conservative House Freedom Caucus, but back home his Richmond-area district was changing. Redistricting in 2016 removed some of the state's rural GOP strongholds, and by 2018 he faced a tough challenger in former CIA operative Abigail Spanberger. Brat tried to run a traditional GOP campaign, tying Spanberger to Nancy Pelosi more than two dozen times in their only debate and campaigned on repealing Obamacare and cutting taxes. But 2018 wasn't a traditional year, and Spanberger racked up strong margins in the diverse, affluent suburbs to overcome Brat's strength in the rural areas.

Sen. Orrin Hatch, R-Utah

The 84-year-old Hatch retires as the longest-serving GOP senator in history. During his 42 year tenure, the Utah Republican has chaired the Senate Judiciary Committee, where he oversaw important judicial nominations, and finally the Senate Finance Committee, helping pass sweeping tax reform last year. Hatch was cozy with Trump, and the president even said he had hoped Hatch would run for another term. Trump may not get along as well with Hatch's successor — 2012 GOP presidential nominee Mitt Romney, who's been critical of Trump in the past. We do hope that Hatch maintains his hilarious Twitter feed when he leaves office though.

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