Some of Donald Trump's friends in Washington suddenly sound nervous about him having the keys to the economy. A few are even talking about wrenching them away.

There are a few nascent efforts to pare back the U.S. president's legal power to set tariffs, now being used in an unprecedented manner.

Those efforts are a longshot. What's most significant isn't whether they will happen, at least not yet. What's most significant is what they reveal.

And what they reveal is nervousness among Trump allies — on Capitol Hill, which apparently was as stunned by the scope of his tariffs as Wall Street was.

Take Ted Cruz. The Texas senator says he's fine if Trump is doing this as a negotiating ploy. But he's worried Trump might actually be serious about keeping tariffs in place forever.

If these tariffs on allies remain for 30 days, 60 days, 90 days — still damaging the economy — that's a terrible outcome, Cruz says. And he fears this might actually be the plan.

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He made a surprisingly stark prediction about what this would mean in next year's midterm elections, if the tariffs cause a recession.

"In all likelihood, politically, it would be a bloodbath," Cruz said on his podcast Friday. "You would face a Democrat House, and you might even face a Democrat Senate."

Wall Street did not expect Trump to follow through, Cruz said, a point underscored by the eye-popping 10 per cent drop in the S&P 500 index this week.

The Republican also pushed back on the idea that these tariffs will only hurt foreigners, or foreign companies. He said a major American car company told him it now expects to increase the average price of a vehicle by $4,500 by this summer.

To his point, it's not clear what Trump's goal is. The White House is sending mixed messages. 

On the one hand, the official line is that these tariffs are mostly permanent, and that they'll help raise tax revenue. Yet Trump is also talking about negotiating with Canada. On Friday he suggested he might do the same with Vietnam, after it offered to eliminate its tariffs. 

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Cruz isn't alone in his consternation.

A couple of Republicans told CNN they're hoping for evidence — quickly — that this is just a negotiating ploy.

Wisconsin Sen. Ron Johnson said: "Right now, I'll give [Trump] the benefit of the doubt, but I'm concerned."

One of them, Sen. Thom Tillis of North Carolina, who is facing a tough re-election fight, said farmers in his state are one crop away from bankruptcy: "They don't have time."

Baby steps in Congress  

So what are these senators doing about it?

After all, the U.S. Constitution gives the Congress power over tariffs. But since the Second World War it's allowed the president to impose them in an emergency.

Now, a number of lawmakers are talking about setting limits. The effort is mostly led by Democrats, but there's evidence some Republicans want to help.

It began with the four who voted to revoke Trump's tariffs on Canada; that measure passed the Senate this week, but appears doomed in the House.

There's an effort nevertheless in the House to force a vote on the measure. Democrats have begun a complicated process to push the issue to the floor.

In addition, the longest-serving Republican in the Senate, third in line to presidential succession, is co-sponsoring his own bill. Chuck Grassley's measure would require congressional approval for tariffs, or they would expire in 60 days.

It's worth noting, again, that these measures are, to put it mildly, longshots. Even if, by some political miracle, they got through both chambers of Congress, it's virtually inconceivable that they would receive enough votes to withstand a Trump veto.

It's the context that's telling.

Democrats smell a political winner

There was no doubt which party, on Friday afternoon, believed it had the upper hand on this issue. Democrats are now hungry to talk tariffs. 

They have been flailing desperately since last year's election for a message to focus on, now that they're in opposition.

The party's top figures held their second news conference of the week on this topic on Capitol Hill on Friday, announcing efforts to tack an anti-tariff measure onto a budget bill working through the Senate.

Speaking of Trump's tariffs, top Senate Democrat Chuck Schumer said they are: "one of the dumbest decisions he's ever made as president — and that is saying a lot."

Promoting his party's line, Schumer described the tariffs as a class issue: a de facto tax on the middle class, to generate revenues used for tax cuts on billionaires.

"It's a disgrace," he said.

Sen. Ben Ray Luján of New Mexico said Republicans had better never talk about economic responsibility again. "Because they're about to throw it out the door," he said. 

And on a day that the stock market was melting down, and U.S. relationships were in shambles, and the world was talking about retaliating, here's another telling sign.

The story barely rated a mention anywhere on the Fox News website Friday afternoon, and only occasionally came up on its TV network. It wasn't hard to tell who saw this issue as a political winner Friday. And who didn't.