President Trump speaks during a news conference at the Group of Seven summit Saturday in La Malbaie, Quebec. (Evan Vucci/AP)

President Trump has remained largely unchecked by Congress as he swipes aside decades of U.S. trade policy, goads allies and imposes tariffs that analysts say could punish American producers and consumers as much as they hurt other countries. 

And that seems unlikely to change, even after a weekend of chaos at the Group of Seven summit in Quebec, where Trump doubled down on his tariffs against Canada, Mexico and the European Union and then lashed out at the Canadian prime minister on Twitter. 

A few Senate Republicans are attempting to put some checks on the president through legislation that would give Congress veto power over tariff decisions made on the basis of national security. But their effort appears destined to fail, seemingly leaving Trump with free rein to undo U.S. trade relations around the world as he sees fit. 

His party cannot summon the will to stop him, and Democrats, divided against themselves on the issue, cannot speak with a unified voice in opposition. 

“I don’t think having that fight right now is necessary,” Sen. John Cornyn (Tex.), the No. 2 Senate Republican, said Monday, summing up the views of a number of GOP senators about legislation authored by Sens. Patrick J. Toomey (R-Pa.) and Bob Corker (R-Tenn.) to give Congress a say in some presidential trade decisions.

Sen. Patrick J. Toomey (R-Pa.) on Capitol Hill in November. He is co-sponsoring legislation aimed at curbing some of President Trump’s protectionist trade measures. (Melina Mara/The Washington Post)

 For congressional Republicans, it is unclear whether the time to have that fight will ever come, although if Trump goes forward with threats to impose tariffs on auto imports, the economic fallout in key states could ratchet up the pressure on Congress to respond.

But mostly, Republicans have spent a year and a half trying to argue Trump off the protectionist views that were central to his 2016 campaign, via countless meetings, letters, published opinion pieces and public statements. They have had relatively little success, although some congressional Republicans count it as a victory that the administration is renegotiating the North American Free Trade Agreement rather than exiting it altogether. 

Trump, meanwhile, has grown emboldened in tossing aside the principles of free trade that have for decades helped define the GOP. Within the White House, advisers such as Peter Navarro who embrace protectionist views are on the upswing. And if Trump is getting countervailing advice from others, such as Treasury Secretary Steven Mnuchin, he appears to be disregarding it.

Democrats are themselves split on trade, with some in the party supporting Trump’s approach, making it difficult to offer unified pushback against the risky new course Trump is charting. 

Senate Majority Leader Mitch McConnell (R-Ky.) and House Speaker Paul D. Ryan (R-Wis.) have argued that continuing to reason with the administration is a better course than legislation. But Toomey said in an interview that talk is no longer enough. 

Senate Majority Leader Mitch McConnell (R-Ky.), center, and other GOP leaders speak to the media last week. (J. Scott Applewhite/AP)

“We will continue having discussions with the administration, but we can’t limit ourselves to talking about it when counterproductive measures are being taken,” Toomey said. 

Toomey said Trump called him Sunday night from Singapore, ahead of his meeting with North Korean leader Kim Jong Un, to defend imposing tariffs on steel and aluminum from Canada, Mexico and the E.U. in the name of national security.

But Toomey said he remained determined to try to get a vote on the legislation. Although McConnell has branded it an “exercise in futility” since Trump would not sign the bill, Toomey and Corker hope to bring the measure up as an amendment to a defense policy bill on the Senate floor this week. It is uncertain whether they will succeed, although Corker said senators should have more interest in their measure after the events at the G-7, where Trump withdrew from a carefully crafted joint statement in a fit of pique while lashing out at the trade policies of Canada and other countries. 

“I would think that more people would be inclined to want to support a piece of legislation that allows us to weigh in on any final product,” Corker said. “That would be, I think, the natural impulse of people who saw what happened.”

Already about a dozen senators from both parties have sponsored the Toomey-Corker bill, and other Republicans have sounded open to it. 

“It appeals to me — I’ll put it that way. I’ll have to see what the final result is, but, yeah, it appeals to me,” Sen. Orrin G. Hatch (R-Utah) said Monday. “I think the president’s got to realize we have an obligation here, and I’m pointing that out to him.”

Hatch was also critical of Navarro’s comment that there’s a “special place in hell” for Canadian Prime Minister Justin Trudeau for how he has handled the trade issue with Trump. 

“I thought he should’ve kept his big mouth shut,” Hatch said. “Because I don’t think that helps us in foreign policy, and I think frankly it was out of line.”

But other Republicans showed little interest in the Toomey-Corker proposal. “I haven’t heard a compelling case,” said Sen. Deb Fischer (R-Neb.). “The sponsors of the bill need to make that.”

For months, as Trump has threatened to engage a trade war with U.S. allies and antagonists alike, some GOP lawmakers have voiced regret that Congress has ceded so much authority to the executive branch over trade, an area that the Constitution assigns to the legislative branch. That approach worked well under previous administrations, at least in the view of most congressional Republicans who hewed to the party’s traditional support for free trade. But now that Trump has turned the calculus upside down, it may be too late for Congress to get its authority back. 

In the case of the tariffs of 25 percent on imported steel and 10 percent on aluminum levied against Mexico, Canada and the E.U., Trump used his authority under Section 232 of the Trade Expansion Act of 1962 to limit imports if the commerce secretary finds that they threaten national security. Lawmakers in both parties have argued that Trump abused his authority in using that rationale against some of the United States’ closest allies. 

And Trump undercut his argument over the weekend by declaring on Twitter that the measures were in response to Canadian tariffs on dairy. 

“Over the weekend it’s become clear that the administration’s push on steel and aluminum tariffs isn’t about national security but is in fact a response to what they see as trade problems in other nations,” said Neil Bradley, executive vice president at the U.S. Chamber of Commerce. “If that’s the reason, it’s only logical that Congress is going to want to reassert its authority over tariffs.” 

But GOP-leaning trade groups such as the Chamber of Commerce have become just more voices that Trump ignores. 

“We are all considering how best to respond to this unprecedented degree of disunity and rancor between the U.S. and our closest trading partners,” said Rufus Yerxa, president of the National Foreign Trade Council. “The real winners are China and Russia, who prosper from this disastrous decline in American leadership and a crisis in liberal democracies worldwide.”

David Lynch contributed to this report.