WASHINGTON — The lack of widespread Republican condemnation of President Trump for his comments about four Democratic congresswomen of color illustrated both the tightening stranglehold Mr. Trump has on his party and the belief of many Republicans that an attack on progressivism should in fact be a central element of the 2020 campaign.
While a smattering of Republicans chastised Mr. Trump on Monday, most party leaders in the House and Senate and much of the rank-and-file remained quiet about the president’s weekend tweets directing dissenters to “go back” where they came from. He followed up on those comments on Monday with harsh language directed at “people who hate America” — an inflammatory accusation to be leveled against elected members of the House.
With Mr. Trump far more popular with Republican voters than incumbent Republican members of Congress, most are loath to cross the president and risk reprisals. The case of Representative Justin Amash, the Michigan lawmaker who was forced to leave the party after he dared to suggest Mr. Trump should be impeached, serves as a cautionary tale.
At the same time, many Republicans are seeking to label the four congresswomen and their ideas as “far left,” seeing it as a potential foundation of a sweeping critique of Democrats in 2020. In an appearance on Fox News, Senator Lindsey Graham, Republican of South Carolina, called the four “a bunch of communists,” a step beyond the president, who said he was at the moment only willing to go so far as calling them “socialists.”
Both the willingness of Republicans to attach extremist labels to Democrats and the Democratic assault against Mr. Trump as a racist and white supremacist presage a particularly bitter 2020 campaign.
Even those lawmakers who took Mr. Trump to task were careful to underscore their differences with the political and policy views of the House Democrats at the center of the storm — Representatives Rashida Tlaib of Michigan, Alexandria Ocasio-Cortez of New York, Ayanna S. Pressley of Massachusetts and Ilhan Omar of Minnesota.
Senator Mitt Romney of Utah, one of the few Republicans who has criticized Mr. Trump since he became president, told a Boston TV station that while the president might have gone too far, “I certainly feel that a number of these new members of Congress have views that are not consistent with my experience and not consistent with building a strong America.”
“I couldn’t disagree more with these congresswomen’s views on immigration, socialism, national security and virtually every policy issue,” said Senator Patrick J. Toomey, Republican of Pennsylvania. “But they are entitled to their opinions, however misguided they may be.”
Senator Thom Tillis, a North Carolina Republican who faces a potentially difficult re-election campaign next year, sought to dodge the debate over the president’s comments and focus on the differences between the parties. “The reality is I want to shift back to the issues and the America they represent versus the America that I want to see,” Mr. Tillis told reporters.
The rapid approach of the 2020 campaign has drawn Mr. Trump and Republicans on Capitol Hill closer as the lawmakers see their fate inextricably linked to the president, diminishing any possibility that they would break from Mr. Trump.
And the spotlight put on the Democratic presidential candidates and the advocacy by some of them for eliminating private health insurance in favor of a government program, sweeping revisions in the tax code and the institution of liberal immigration policies have galvanized Republicans.
They see Mr. Trump, as outrageous and unpredictable as he might be, as far preferable to any of the Democrats.
“I’m not going to vote for a socialist,” said Senator Cory Gardner of Colorado, perhaps the most endangered Republican in the Senate, who has made clear he is firmly allied with the president.
Republicans may cringe at some of Mr. Trump’s crude comments and insults. They may wince at his easily unmasked falsehoods. They may roll their eyes at his lack of understanding of government fundamentals. To many, his personality itself is off-putting. But he is now their guy.
Despite occasional rifts, Republicans have in the main tried to ignore Mr. Trump’s nearly daily Twitter battles.
Senator Mitch McConnell, the Kentucky Republican and majority leader, routinely refuses to engage when pressed about remarks by Mr. Trump that have electrified social media. Other Republicans say they do not see it as their job to be political pundits or to join with the news media and Democrats in castigating Mr. Trump. They also believe that, in most cases, the firestorm lasts only so long and will be quickly followed by the next iteration, making it pointless to get caught up in the repeating cycle.
Over the course of the administration, most Republicans have grown accustomed to Mr. Trump’s fiery outbursts and practiced in how to avoid commenting on them. They find the president, a man who wields his cellphone like a weapon, to be almost always accessible, cajoling and complimenting lawmakers who appreciate the attention.
They have also gained experience in how to diplomatically push back against the president and challenge his views when they differ — though usually in private to avoid inciting his ire.
“My personal recipe for a productive relationship with the president is to work with him in public all I can,” said Senator John Cornyn, Republican of Texas. “When we have disagreements, as we’ve had on tariffs and things like that, we talk in private, try not to embarrass him or ourselves. I’ve found that’s a good way to handle it.”
Recognizing this pattern, Senator Chuck Schumer of New York, the minority leader, accused Senate Republicans on Monday of cowardice. “It’s become frighteningly common for many of my Republican colleagues to let these moments sail by without saying even a word,” Mr. Schumer said. “Republican leadership — especially — rarely criticizes the president directly even in a situation like this that so clearly merits it.”
Jeff Flake, the former Arizona Republican senator whose feud with Mr. Trump helped end his congressional career, said he sympathized with the desire of his former colleagues not to address every comment made by Mr. Trump. “But there are times when the president’s comments are so vile and offensive that it is incumbent on Republicans to respond and condemn,” he said on Twitter. “This is one of those times.”
Those hoping for a wide rupture between the president and the more conventional Republican politicians on Capitol Hill say they have finally come to terms with the reality that no break is in the offing with the economy prospering, the election looming and the Trump administration so far avoiding a cataclysmic foreign policy blunder.
“They have made their bed and are trying to sleep in it and hope they don’t have nightmares,” said William Kristol, the conservative Trump critic. “They don’t feel like they are paying a huge price.”
Mr. Kristol said he once believed that the combination of the 2018 election results, the extended government shutdown and the departure of Defense Secretary Jim Mattis — a source of comfort for Republicans who feared Trump would do something rash with the military — might give congressional Republicans pause. But any deep distress that existed seems to have dissipated.
“I am more pessimistic about the notion that the Republican Party will throw off Trump than I was a year ago,” he said.
Instead, Republicans worry that, even at a moment when the president is stirring division, a perceived slight or unwarranted criticism could lead Mr. Trump to throw them off, an outcome that could be ruinous to their political careers.