Donald Trump's trade agenda will face a new source of friction if Democrats win control of Congress on Tuesday, with a cascade of oversight hearings and symbolic tariff rollback votes likely next year, but Trump will remain undeterred in his zeal for more tariff actions, trade experts and congressional aides say.

Democrats are eager to pass legislation to negate many of Trump's tariffs and the more archaic statutes backing them, but any gains by the party will run into the reality of Trump's veto power.

"One of the most obvious priorities would be repealing Trump’s tariffs on Canada, which are raising prices and harming communities on both sides of the border," said Senator Ron Wyden, the top Democrat on the tax- and trade-focused Senate Finance Committee.

Democrats need a net gain of four seats in both the US House of Representatives and the US Senate to overturn Republicans' narrow 218-214 and 53-47 majorities. Opinion polls favor Democrats to win the House, while the Senate remains too close to call, leaving Democrats far short of a veto-proof two-thirds majority.

Meanwhile, the Trump administration is developing plans to rely more heavily on executive actions, including on trade, without the need for congressional approval.

If they win at least one chamber, Democrats could stage symbolic votes on long-sidelined trade bills such as Senator Chuck Schumer's "End Trump's Tariff Tax Act," which would scrap the statute backing the punitive tariffs on Canadian goods, Section 338 of the Tariff Act of 1930, along with the statute used for Trump's temporary 10% global tariffs, Section 122 of the Trade Act of 1974.

The bill, with 28 co-sponsors including Wyden, also calls for refunding all duties collected under the archaic trade laws.

"Democrats are going to try a lot of things. I just don't think anything's going to get across the finish line because neither party will have a veto-proof majority in any scenario," said William Reinsch, non-resident adviser to the Center for Strategic and International Studies in Washington.

But gaining control of trade committee gavels would give Democrats a platform to launch a steady stream of oversight hearings and investigations into Trump's trade policies, Reinsch and other trade experts said.

Key oversight targets would include shedding light on the opaque process for determining tariff exemptions that benefit specific companies, how tariffs are impacting small businesses, and how the Trump administration is doling out hundreds of billions of dollars in investment funds pledged by Japan, South Korea and other trading partners in recent trade deals.

A confrontational oversight agenda from Democrats would mark a shift from Republicans' largely hands-off approach to Trump's tariffs, which has persisted for two years despite recent pushback from some struggling Republican incumbents, including Senator Susan Collins of Maine.

Coupled with some symbolic tariff rollback votes staged by Democrats, this will start to shift the trade debate to influence the 2028 election cycle, said Greta Peisch, a former general counsel at the US Trade Representative's office and a former trade counsel to Senate Finance Committee Democrats.

Even if Democrats can't muster the votes to pass a bill to reform trade authorities right out of the gate, the effort could "form the basis of a proposal for the presidential elections," said Peisch, now a trade partner at Wiley Rein in Washington.

"I think it's really the beginning of how Democrats, and Congress as a whole, think about whether and how to enact trade legislation and reforms in the next two to four years, really," Peisch added.

The increased noise from Capitol Hill is unlikely to deter Trump from pursuing more tariffs over his final two years in office, including from a forthcoming investigation into excess industrial capacity in 16 major trading partners, even as he grants exemptions or delays some duties.

Trump will continue to pursue his tariff-driven trade agenda aimed at protecting American workers, farmers and businesses from being "ripped off" by past trade deals, White House spokesman Matthew Middleton said.

"President Trump will never waver from putting America First, whether in trade negotiations or through an economic agenda of tax cuts and deregulation," Middleton said in an emailed statement. "That agenda has already secured almost 20 fair trade deals and trillions in manufacturing investments, with even more progress, jobs, and opportunities ahead for everyday Americans." Trading partners also understand Trump's commitment to keeping tariffs in place, and realize that Congress will not be in a position to remove them, said Milos Ivkovic, an international arbitration law expert and adjunct professor at Washington University in St. Louis.

A wait-and-see approach to the vote will not benefit trade deal holdouts such as India, Vietnam or Canada, he said.

"For all of those countries who think that midterms will have such an effect that the United States government and President Trump will change foreign policy, they're mistaken," Ivkovic said. Countries that are holding off on trade discussions with the Trump administration "are actually jeopardizing their negotiations," he added.