Congressional Republicans tried but ultimately failed last week to prevent President Donald Trump from following through with a new policy imposing tariffs on steel and aluminum imports. And despite overwhelming opposition to the policy as crafted, Congress isn’t likely to send a message to the president legislatively, either.

“We ought to push back here. I mean, who are we?” Sen. Jeff Flake (R-AZ), who is seeking to nullify the tariffs legislatively, said in an interview. “I think Republicans and conservatives need to stand up and say, ‘This is not who we are.’”

To Flake’s dismay, GOP leaders on Capitol Hill have suggested that they prefer to work with the administration to narrow the policy, rather than respond legislatively. But other Republicans are warning that without substantive actions now, the administration could impose tariffs on other imports, too—as Congress continues to refuse to exercise some of its most basic constitutional powers under Article I.

“I’ve been worried about the fact that in a number of areas… the legislative branch has outsourced its authority, it’s delegated away its power,” Sen. Mike Lee (R-UT), who has introduced legislation to scale back presidential authority on trade policy, said in an interview. “Whether it’s this president or another president in the future who will go ahead and impose other tariffs and other trade restrictions on other imports in the future.”

But leadership isn’t anxious to bring legislation to the floor, and overcoming a presidential veto would be a difficult feat—especially for this Congress.

“I think the president is listening to some of the concerns that some of us have voiced,” Sen. Thom Tillis (R-N.C.) told The Daily Beast. “As a practical matter, it would be a struggle to get 60 votes in the Senate, and even more so, 291 in the House. So I think it’s better for us just to have constructive dialogue.”

Others warn that stripping a president’s trade authority could set a dangerous precedent. A GOP congressional source told The Daily Beast that House Speaker Paul Ryan (R-WI) was in close contact with Trump to encourage him to narrow the policy such that Mexico and Canada would be exempt from the tariffs. And sources familiar with the tariff process expect that that the new policy would be challenged in court by companies and other entities that would be negatively impacted. These sources pointed out that such lawsuits could be successful because Trump acted under his “section 232” national-security authority to impose tariffs—even though the stated reasons for the tariffs have nothing to do with national security.

But Congress’ hesitance to push back more forcefully against the Trump administration on trade policy underscores a broader reluctance to exercise its constitutional powers to curtail executive authority. Despite widespread concerns among Democrats and Republicans about the president’s apparent desire to fire special counsel Robert Mueller, Congress hasn’t acted on legislation aimed at shielding Mueller from political interference. And both the House and Senate have failed to advance measures that would dial back Trump’s war-making and surveillance powers.

Republicans weren’t likely to change Trump’s mind on the tariffs. For decades, Trump has espoused protectionist views on trade that would align him more with the populist left than the free-market right. And with free-trade proponent Gary Cohn exiting from his role as top economic adviser at the White House just as the new tariff policy was being crafted, GOP lawmakers weren’t optimistic that they’d have an ally in Cohn’s replacement—whomever that may be.

Lawmakers are considering at least two pieces of legislation as a response to the new tariffs. One is the Global Trade Accountability Act, a proposal authored by Lee that would require Congress to approve any trade-related policies imposed by the executive branch.

“I don’t see a path forward where the president would receive it well,” Tillis said.

Another measure is being crafted by Flake, a longtime supporter of free trade who has been critical of Trump on a number of fronts—even suggesting that a Republican who shares his views should challenge Trump for the Republican nomination in 2020. Flake’s legislation will aim to nullify the steel and aluminum tariffs altogether.

For many of Flake’s counterparts, though, now isn’t the right time to upend ongoing conversations with the administration about further narrowing the tariffs policy to include more exemptions for certain countries.

“I think it’s a little quick to turn to either the Flake or the Lee bill,” Sen. Roy Blunt (R-MO), a member of Senate Republican leadership, told The Daily Beast. “I’m concerned about the current trade policy, but I’m not of the view that it’s time yet to re-do the executive structure in that policy.”

Even some of Trump’s staunchest allies on Capitol Hill are opposed to the new tariff policy, and many of them have aired their frustrations to the president directly. And while many of them would be inclined to support legislative action in response, they believe Flake isn’t the right person to carry the free-trade banner—not because of his longstanding views in support of free trade, but because of his opposition to Trump.

“What could have been a cordial disagreement over policy is now a rallying cry for Never Trumpers,” a senior GOP aide told The Daily Beast. “Members who support free trade now risk the ire of Trump and receiving the ‘Flake treatment.’ Most conservatives will calculate that it’s not worth the risk and now the pushback is dead on arrival. It’s a shame because this is a genuine instance of where Congress should assert Article I authority.”

One Senate Republican aide implored lawmakers to take the rare opportunity to curtail executive power over a policy that nearly everyone on Capitol Hill opposes.

“President Trump’s unilateral action on tariffs is a tremendous opportunity for both parties to come together and limit executive branch power,” the aide told The Daily Beast. “I hope the Democrats don’t waste it.”

But Democrats on Monday didn’t seem eager to join Republicans’ attempts to push back against the administration based on the substance of the policy.

“I think the process the president followed to make his tariff decision and to announce it has troubled a lot of my colleagues was troubling because it was clear that it wasn’t fully vetted through the different departments and the White House,” Sen. Chris Coons (D-DE) told The Daily Beast.

Aside from their opposition to the policy itself, Republicans are concerned that the tariffs could upend the economic message they’re hoping to use with voters in the upcoming midterm elections, especially on the heels of the tax-cut legislation. In particular, they worry that the tariffs could function as a tax hike on consumers at the same time that they plan on touting a booming economy.