"After much thought, consideration and family discussion over the past year, Elizabeth and I have decided that I will leave the United States Senate when my term expires at the end of 2018," Corker said in a statement.
2. Sen. Jeff Flake of Arizona; announced on 10/24/17
Flake, also a frequent critic of Trump, announced his retirement in a blistering speech on the Senate floor that bemoaned the "coarsening" tenor of politics in the United States.
Flake denounced the "complicity" of his own party in what he called an "alarming and dangerous state of affairs" under Trump, blaming the President for setting the tone. In his speech, Flake assailed a "flagrant disregard for truth or decency" and attacked a "regular and casual undermining of our democratic norms."
"When such behavior emanates from the top of our government, it is something else: It is dangerous to a democracy," Flake said.
House of Representatives
3. Rep. Sam Johnson of Texas; announced on 1/6/17
The longtime congressman made his announcement in a message posted to his website.
"After much prayer, I have decided I will not seek re-election to serve the Third District of Texas in the U.S. House of Representatives in 2018," Johnson said in the statement. "This will be my final term in the appropriately named 'People's House.' "
4. Rep. Lynn Jenkins of Kansas; announced on 1/25/17
Jenkins announced she would instead work in the private sector, shutting down rumors that she might run for Kansas governor.
"With the unique opportunity given to us by the American people, with Republican majorities in the House, the Senate, and now a newly inaugurated President, this is a time for action and serious policy making. This is a time for fighting for Kansas and making the tough calls; not fundraising and campaigning," Jenkins said in a statement.
She continued: "In two years, at the conclusion of this Congress, I plan to retire and explore opportunities to return to the private sector, allowing a new citizen legislator to step up and serve Kansans."
5. Rep. Ileana Ros-Lehtinen of Florida; announced on 4/30/17
Ros-Lehtinen, the first Cuban-American elected to Congress, is retiring after 38 years -- handing Democrats a major opening to pick off a GOP-held seat.
She announced her decision in an interview with The Miami Herald. She has been a key moderate voice in the House, but she said her decision had nothing to do with her differences with Trump.
"I've served under all kinds of different dynamics in all these years that I've been in office here," she told the newspaper. "Though I don't agree with many, if not most, positions of President Trump."
6. Rep. John J. Duncan Jr. of Tennessee; announced on 7/31/17
Duncan, who served for three decades, made his announcement to the Knoxville News Sentinel.
"It has been a very special privilege to represent the people of the Second District in the U.S. House of Representatives," the Knoxville Republican said. "However, I will not be running for re-election in 2018."
7. Rep. Dave Reichert of Washington state; announced on 9/6/17
Reichert is a moderate Republican in a swing seat, which could be at play in the 2018 midterms.
"After spending time during the August work period with family and friends, reflecting on the past, discussing the future, and celebrating another birthday, I have decided this will be my last term," Reichert said in a statement.
He is one of 23 Republicans who represent districts Hillary Clinton carried in the 2016 presidential election.
8. Rep. Charlie Dent of Pennsylvania; announced on 9/7/17
Dent, also a moderate, said Thursday that while Trump hadn't been the determining factor in his decision to retire at the end of his term, he was a part of it.
"Well, at least in my case, I would say the President was a factor, but not the factor for me deciding to leave," Dent told CNN's Poppy Harlow. "A very challenging midterm environment" also contributed to his decision, he said.
9. Rep. Dave Trott of Michigan; announced on 9/11/17
Trott's announcement opened up a competitive House seat for the 2018 midterms.
"Representing the Eleventh District has been an honor, but I have decided not to seek re-election in 2018," Trott said in a statement. "This was not an easy decision, but after careful consideration, I have decided that the best course for me is to spend more time with my family and return to the private sector."
10. Rep. Pat Tiberi of Ohio; announced 10/19/17
The senior congressman said he plans to leave Congress to lead the Ohio Business Roundtable.
"While I have not yet determined a final resignation date, I will be leaving Congress by January 31, 2018," he said in the statement. "I have been presented with an opportunity to lead the Ohio Business Roundtable that will allow me to continue to work on public policy issues impacting Ohioans while also spending more time with my family."
11. Rep. Jeb Hensarling of Texas; announced on 10/31/2017
The powerful chairman of the House Financial Services Committee, who represents Dallas, hails from a Republican-heavy district.
In an email sent to his supporters, Hensarling said it was never his intention to make congressional service a career.
"Although service in Congress remains the greatest privilege of my life, I never intended to make it a lifetime commitment, and I have already stayed far longer than I had originally planned," he said.
12. Rep. Lamar Smith of Texas; announced on 11/2/2017
Smith, the chairman of the House Science Committee, said he hopes to stay in politics.
"For several reasons, this seems like a good time to pass on the privilege of representing the 21st District to someone else," Smith, who has served since 1987, said in a statement. "I have one new grandchild and a second arriving soon! And I hope to find other ways to stay involved in politics."
13. Rep. Frank LoBiondo of New Jersey; announced on 11/7/2017
He announced his decision in a statement, saying it was not "health-related" or "electoral," and he bemoaned the polarized nature of Congress.
"As some of my closest colleagues have also come to realize, those of us who came to Congress to change Washington for the better through good governance are now the outliers," LoBiondo's statement read. "Today a vocal and obstinate minority within both parties has hijacked good legislation in pursuit of no legislation."
LoBiondo has been in the House since the 1990s.
14. Rep. Ted Poe of Texas; announced on 11/7/17
He announced in a statement on Twitter, adding that he was proud of the work he had done during his time in office.
"I will continue this work every day until I retire at the end of this term," Poe said. "And that's just the way it is."
15. Rep. Bob Goodlatte of Virginia; announced on 11/9/17
Goodlatte, the chairman of the House Judiciary Committee, announced just two days after a stunning defeat by GOP candidates in statewide and local contests in Virginia.
In a written statement, Goodlatte said he and his wife had discussed the 2018 midterm election and his time as chairman coming to an end in 2018 was a factor.
"After much contemplation and prayer, we decided it was the right time for me to step aside and let someone else serve the Sixth District," Goodlatte wrote. "I will not seek re-election. With my time as Chairman of the Judiciary Committee ending in December 2018, this is a natural stepping-off point and an opportunity to begin a new chapter of my career and spend more time with my family, particularly my granddaughters."
16. Rep. Joe Barton of Texas; announced on 11/30/17
Barton, the longest serving member of the Texas House delegation, announced he would not seek re-election following a scandal that involved a nude photo of him surfacing on Twitter.
After the photo leaked, Barton apologized for not using "better judgment."
"While separated from my second wife, prior to the divorce, I had sexual relationships with other mature adult women," Barton said in a statement first reported by The Texas Tribune. "Each was consensual. Those relationships have ended. I am sorry I did not use better judgment during those days. I am sorry that I let my constituents down."
17. Rep. Blake Farenthold of Texas; announced on 12/14/17
Farenthold, who's been under fire for accusations of sexual harassment, announced he is not planning to run for re-election in a video.
"I'd never served in office before. I had no idea how to run a congressional office. And as a result, I allowed a workplace culture to take root in my office that was too permissive and decidedly unprofessional," he said in the video. "I understand fully that this issue has become a political distraction and I would be forced to engage in a monthlong campaign for personal vindication. Quite simply, my constituents deserve better. Therefore I'm announcing my decision not to run for re-election."