“For too long, Congress has delegated its clear authority to regulate interstate and foreign commerce to the Executive Branch,” Sen. Chuck Grassley (R-IA), a top Republican who chairs the chamber’s Judiciary Committee, said in a statement.

Grassley, a member of the Finance Committee and third in line to the presidency as Senate president pro tempore, unveiled a bipartisan bill to do just that by requiring tariffs to expire within 60 days unless approved by Congress.

“I’ve talked for years about the fact that over the last century, Congress has delegated a lot of power to the Executive Branch,” said Sen. Mike Lee (R-UT), who has long pushed to require congressional consent for the sort of national emergency declarations Trump is using to impose tariffs.

Since the height of the Great Depression in the 1930s, Congress has increasingly ceded its control over tariffs to presidents. The Trade Act of 1974 accelerated that trend, expanding the power for presidents to reach trade agreements and levy tariffs.

Conservative tariff critics, such as Sen. Rand Paul (R-KY), who was among the Republicans who voted to overturn Trump’s Canadian tariffs, say tariffs are a tax that should only be levied by Congress. However, Republicans on the other side of the argument see Trump as following through on a core campaign promise using mechanisms that have long been at presidents’ fingertips.

“It’s amazing, isn’t it? All of a sudden, they wake up to discover, ‘Wait a minute, for 50 years, we’ve given the president authority,’” Sen. Josh Hawley (R-MO), who said autoworkers in his state are “absolutely thrilled” with the tariffs, told the Washington Examiner. “If they want to revisit that, more power to them. But I think on the underlying policy, let’s give the president time to work.”

The political reality is that Congress has no immediate plans to claw back the power it relinquished decades ago. Even Republicans with tariff anxiety who support the notion of curtailing a president’s authority are adamantly behind Trump’s long-term vision that countries will come to the negotiating table and domestic manufacturing will boom. They’re urging for patience with a “wait-and-see” approach.

“I think there’s something to be said for having congressional review. Then that becomes incendiary, and everybody’s going to report that there’s a rift between us and the administration, which is bull,” Sen. Thom Tillis (R-NC) said. “The reality is that that’s sort of a guiding detail. We don’t have that now, and so we have to put our faith in [Commerce Secretary Howard Lutnick’s] strategy here.”

Sen. Mike Rounds (R-SD) cited an unfavorable political climate for curbing Trump’s power, which would be touted as a win for Democrats and a loss for Republicans.

“I’m fully in support of that,” Rounds said of reining in executive power. “But when you do it, you have to do it in a neutral environment, where you have Republicans and Democrats not being forced to choose against their own party’s person in office when there is a tariff in question.”

Ultimately, Republicans are gearing up for tough political months ahead on the fallout from Trump’s tariffs that cratered markets at the opening bell on Thursday.

Sen. John Kennedy (R-LA), known for his humorous and unorthodox similes, compared tariffs to drinking whiskey.

“A little whiskey under the right circumstances will refresh you. Too much whiskey under the wrong circumstances will make you drunk as a goat,” Kennedy said. “That’s why I say it’s more art than science.”

Inflation will not “necessarily” ensue, he added, citing Trump’s more modest first-term tariffs and trade barriers from other countries. He predicted the true effects would not be known for three to four months.  

“This is a bold and reasonably risky move. It just is,” Sen. Ron Johnson (R-WI) said. “The president has to understand that as well. He believes this is exactly what he has to do, OK? And I hope he is right. I hope the naysayers are wrong. I don’t know.”

Senate Majority Leader John Thune (R-SD), who’s previously expressed concern over the effect of tariffs on his state’s agriculture industry, walked a political tightrope.  

“Reciprocal tariffs [are] something that I think most people think makes sense,” Thune said. “But obviously, you want to make sure that you’re not doing harm to the economy, in particular sectors of the economy, and I think that’s something they’ll probably monitor pretty carefully.”

Meanwhile, Democrats have jumped at the opportunity to go on the offensive against a divided GOP. Democrats have faced their own inner turmoil as they clamber for a cohesive strategy to combat Trump with minorities in both chambers.

Sen. Tim Kaine (D-VA) passed a measure Wednesday night to nullify Trump’s emergency declaration to impose 25% Canadian tariffs after picking up support from a handful of Republicans, including Paul. The measure is likely to die in the House. Kaine has similar legislation in the works to target other tariffs.

Sen. Maria Cantwell (D-WA), co-author of Grassley’s tariff legislation, said the subject is likely to be a reoccurring theme for Democrats in the coming days during a marathon Senate voting session on amendments for a GOP budget measure to advance Trump’s broader agenda.

“Donald Trump made one of the dumbest decisions he has ever made as president, and that’s saying something,” Senate Majority Leader Chuck Schumer (D-NY) said. “It is the largest tax hike on families since World War II.”

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Trump’s tariffs didn’t impose additional reciprocal duties on Russia but stretched to remote corners of the globe, including uninhabited islands and territories home to more penguins than humans.

“Donald Trump slapped tariffs on penguins and not on [Russian President Vladimir] Putin,” Schumer said.

David Sivak contributed to this report.