The 2018 midterm elections on Tuesday, Nov. 6, will give President Trump his first chance to defend the Republican Party's Senate and House majorities. Already, however, several Republicans in Congress have announced they won't be running for re-election. Here's our running list:

Sen. Bob Corker, R-Tenn

  • After tangling with President Trump, including questioning his "stability" and "competence," Corker put an end to speculation and announced he would not be running again in 2018. Corker and Trump have since engaged in multiple scraps on Twitter, Corker calling it "a shame the White House has become an adult day care center" and Trump saying Corker "couldn't get elected dog catcher."

Rep. Charlie Dent, R-Pa.

  • Dent, a centrist Republican, announced in September that he'd decided against running for re-election after consulting with family and advisers. Pennsylvania state Rep. Justin Simmons had announced he would challenge Dent in the primary.

• Rep. John Duncan, R-Tenn.

Sen. Jeff Flake, R-Ariz.

  • Flake confirmed his decision in a Senate floor speech in October and condemned the current state of politics, specifically President Trump, as one of the main reasons he's deciding to step aside.

Rep. Bob Goodlatte, R-Va.

Rep. Jeb Hensarling, R-Texas

  • Speculation had been building that Hensarling would not seek re-election after getting termed out of the House Financial Services chairmanship. Unlike the centrist Republicans who have announced their retirement, Hensarling sees eye to eye with the Trump administration on most issues.

• Rep. Lynn Jenkins, R-Kansas

• Rep. Sam Johnson, R-Texas

Rep. Frank LoBiondo, R-N.J.

Rep. Tim Murphy, R-Pa.

  • Publicly pro-life, Murphy said he would not be running for re-election in 2018 after it was revealed that he had asked his mistress to have an abortion.

Rep. Ted Poe, R-Texas

Rep. Dave Reichert, R-Wash.

  • Reichert faced tense townhall crowds during the August recess, and announced upon returning in September that he had decided "this will be my last term." A number of Democrats were already preparing to try to challenge him. The Democratic Congressional Campaign Committee celebrated afterward that "clearly, Congressman Reichert saw the writing on the wall."

Rep. Ileana Ros-Lehtinen, R-Fla.

  • Cuban-American and the first Hispanic woman elected to Congress, Ros-Lehtinen announced back in April 2017 that she will retire at the end of her current term. Speaker Paul Ryan afterward called her "a force." She has clashed with President Trump on transgender issues, deportations, and his travel ban.

Rep. Lamar Smith, R-Texas

  • Smith made a name for himself as chairman of the House Science, Space and Technology Committee, especially in the last Congress when he often questioned the Obama administration's focus on climate change. In a letter to supporters, he said he has "one new grandchild and a second arriving soon. And I hope to find other ways to stay involved in politics."

• Rep. Pat Tiberi, R-Ohio

• Rep. Dave Trott, R-Mich.

  • A centrist Republican who has criticized President Trump, Trott announced in September after some speculation that he would not seek a third term.

Updates will be added.