Congress has power over tariffs, but stopping Trump isn't likely as of now

President Donald Trump is on a tariff spree — and it's unclear if Congress will try to stop him even as it has the potential power to do so.

Trump unveiled a nearly global tariff regime on Wednesday, slapping a blanket 10% duty on almost every country on the planet and saddling dozens of them with significantly higher tariff rates.

The sweeping policy pronouncement promptly torpedoed stocks in the U.S. and around the world, ratcheting up recession fears and triggering aggressive retaliation by China.

The new U.S. import duties follow other protectionist policies that Trump, who champions tariffs as an economic cure-all, has rolled out since taking office in January.

Trump's executive order implementing his so-called reciprocal tariffs says that he derives his authority for the action from four sources in the United States Code.

Among them are the International Emergency Economic Powers Act and the National Emergency Act.

A president using those laws in tandem can declare an emergency and then impose related tariffs.

Wednesday's order declared a national emergency in response to what it called an "unusual and extraordinary threat" to America's economy and security.

That threat is based on "the domestic economic policies of key trading partners and structural imbalances in the global trading system," the order says.

Trump is the first president to use the IEEPA to impose tariffs, according to the Congressional Research Service.

He first invoked the law in February when he announced new tariffs on Canada, Mexico, and China.

Under the U.S. Constitution, the power to tax and tariff falls squarely within the legislative branch.

Article 1, Section 8 of the Constitution states, "The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises," as well as, "To regulate Commerce with foreign Nations."

But Congress has enacted laws giving the president some tariff powers. And courts have generally upheld that authority.

In the early days of the United States, tariffs were the government's primary source of revenue.

Even after the 16th Amendment, ratified in 1913, implemented the federal income tax, tariffs remained in effect.

After the economic one-two-punch of the Great Depression and the Smoot-Hawley Tariff Act, however, Congress gave the president some leeway over tariffs.

"The primary reason was, it was unwieldy for them," Scott Bomboy, editor in chief of the National Constitution Center, said in a phone interview, referring to lawmakers.

There are now at least six federal statutes delegating some tariff authorities to the president, according to the Congressional Research Service.

As the stock market sell-off deepens, some bipartisan opposition to Trump's tariffs is starting to emerge.

Four Republican senators — Mitch McConnell and Rand Paul of Kentucky, Susan Collins of Maine, and Alaska's Lisa Murkowski — on Wednesday voted alongside all 45 Democrats and two independents to pass a measure that would block Trump's tariffs on Canadian imports.

Democratic Sen. Tim Kaine of Virginia, who authored that resolution, said, "There is going to be massive economic heartbreak in this country" if Congress fails to undo the president's tariffs.

"Donald Trump started in office with the strongest economy in the world," Kaine said, according to NBC News. "He has, in two months, with the chainsaw and the tariffs turned it into one with flashing red lights and question marks. We've got to use the tools at our disposal to get him to do a U-turn."

And a bipartisan Senate bill introduced Thursday would force the president to give Congress 48 hours' notice before imposing new tariffs, and allow Congress 60 days to either approve those duties or let them expire.

"For too long, Congress has delegated its clear authority to regulate interstate and foreign commerce to the executive branch," Sen. Chuck Grassley, R-Iowa, said in a statement Thursday.

"Building on my previous efforts as Finance Committee Chairman, I'm joining Senator [Maria] Cantwell to introduce the bipartisan Trade Review Act of 2025 to reassert Congress' constitutional role and ensure Congress has a voice in trade policy," Grassley said.

But while Congress can pass legislation that repeals or restricts the president's tariff powers, it is less clear whether lawmakers will do so.

Any attempts to rein in Trump's tariffs would likely run into a presidential veto.

And it is unlikely that the Republican-majority House and Senate would override one, much less whether the House would vote to back the Senate's tariff-restricting measures in the first place.

Trump called the effort to undo the Canada tariffs "a ploy" that is "not going anywhere because the House will never approve it and I, as your President, will never sign it."

A more viable path to challenging Trump's tariffs could be through the courts.

A federal lawsuit filed Thursday in Florida argued that Trump's prior use of the IEEPA to impose broad-based tariffs on Chinese imports was unconstitutional.

That emergency law "does not allow a president to impose tariffs on the American people," the New Civil Liberties Alliance, a conservative advocacy group, argues in that suit.

The legal challenge may pose more of a threat to Trump than Congress currently does. But the Congress Research Service notes that judicial precedent "has given the President broad latitude to exercise his tariff authorities."