For nearly two years, fear of triggering a stock market reaction has been the primary brake on President Donald Trump's sweeping tariff campaign against U.S. trading partners around the world. Last week's midterm elections may have introduced a new and more immediate constraint: the ballot box.

That matters beyond Capitol Hill: tariffs are taxes collected on imported goods, which means the fight over them is, at its core, a fight over prices — precisely the issue voters flagged at the polls.

Among the first Republicans to voice open dissent is retiring Rep. Don Bacon, who in February was one of six GOP lawmakers to side with Democrats in a vote to repeal Trump's tariffs on Canada — a rare rebuke of the president's trade policy. Speaking to CNN, Bacon said he was unsure whether Republicans' willingness to oppose the president's trade agenda had grown since the midterms.

"It should," he said. "Trump's tariffs killed the GOP this election."

Polling has consistently shown public hostility toward the tariffs, yet Republican lawmakers have largely avoided commenting on the issue, judging the political cost of crossing the president to be too high. The election results, however, may have demonstrated that silence carries its own significant price. Democrats made major gains at the polls, flipping seats in historically Republican states hit hard by the tariffs — from agricultural states such as Iowa and Kansas to the northern border states of Maine and Michigan.

"Many Republicans were kind of whistling by the political graveyard by ignoring the tariff issue, but now it's come front and center," said Brian Darling, a Republican strategist and former counsel to Sen. Rand Paul of Kentucky.

Nationally, two-thirds of voters said Trump's tariffs had hurt the national economy, according to CNN's Voter Poll.

Some Republicans have already begun to concede that their approach to the tariffs may have exacted a political price. Texas Sen. Ted Cruz, whose state saw significant Democratic gains in the election, pointed to voter frustration over the cost of living as a key factor in the outcome.

"Tariffs have made everything too expensive," Cruz wrote in a post on X last week. "Understandably, people were pissed off, and elected Republicans didn't do enough to address their very real pain," he added.

Cruz has, however, remained a staunch backer of Trump's tariff agenda in Congress.

Even Republicans willing to risk the president's wrath face another formidable hurdle: his veto power. Democrats and their independent allies currently hold 55 of the 100 Senate seats and 255 of the 435 House seats. Even voting unanimously, they would still need at least 12 Republicans in the Senate and 35 in the House to override a presidential veto. That arithmetic makes individual Republican defectors the pivotal variable: any effort to reverse tariffs through Congress needs GOP votes to pass, and then again to sustain an override.

"I'll become Mr. Veto," Trump declared in an Election Day interview on the New York Post's Pod Force One, before the results were in.

In the weeks ahead, the markers to watch are clear: whether more Republicans follow Bacon and Cruz in speaking out, whether additional tariff votes reach the House and Senate floors, and whether the White House follows through on the veto threats Trump has already made public.