Republicans stuck in survival mode after seeing that challenging Trump will end their career: columnist
President Donald Trump listens during a phone conversation with Mexico's President Enrique Pena Nieto on trade in the Oval Office of the White House in Washington, DC on August 27, 2018. (AFP / Mandel Ngan)

The political landscape is littered with former Republican lawmakers who challenged President Donald Trump -- and lost.

Republicans have been silent -- again -- about the president's racist attack on four first-year Democratic congresswomen, following a pattern that has taken hold since Trump first announced his 2016 candidacy, reported the Washington Post.

House Speaker Paul Ryan (R-WI), Sen. Bob Corker (R-TN), Rep. Martha Roby (R-AL) and Rep. Mia Love (R-UT) have all spoken out against Trump -- and all of them no longer hold elected office.

"Republicans who have spoken out forcefully and memorably about Trump are no longer Republican officeholders," wrote Post columnist Amber Phillips. "It is overly simplistic to say these Republicans retired because of their battles with Trump — though in Ryan’s case, a new book suggests that might be true. But all of them saw the writing on the wall: I can either speak out about Trump, or keep my job. In this Republicans Party, you can’t do both."

Rep. Chip Roy (R-TX) took a step toward calling out the president, tweeting that Trump "was wrong to say any American citizen, whether in Congress or not, has any ‘home’ besides the U.S.” -- although he made sure to point out he supported the administration's immigration policies.

"Self-preservation is the default mode of any politician," Phillips wrote. "Most of the congressional survivors of Trump’s takeover of the Republican Party went into that mode when Trump attacked a federal judge, and again when he didn’t forcefully stand up for peaceful people protesting white supremacy. So when Trump attacks Democratic lawmakers, who are regular boogeymen on Fox News anyway, there’s no political incentive for Republicans to say anything about it."

"That’s the way Trump has engineered the Republican Party, to be able to get away with whatever he wants to say," she added. "And it’s working."