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The fight over President Trump's border wall has exposed deep bipartisan fears over something else - the worry that Congress has given away too much power to the president over the years. Democrats and at least a handful of Republicans now say Trump went too far when he declared a national emergency to build a wall on the border with Mexico.
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The Senate is expected to vote Thursday on a resolution that would block Trump's move. The House has already passed it. The president says he will veto the measure. NPR's Kelsey Snell reports on Congress' growing anxiety over how much power Trump or any president can wield.
KELSEY SNELL, BYLINE: At least four Senate Republicans are preparing to do something that they don't do very often - vote with Democrats against President Trump's move to build the wall on the border with Mexico. Kentucky Republican Rand Paul is one of them, but he says this isn't about the wall at all. It's about defending the power of Congress.
RAND PAUL: Most grade school people know Congress spends the money, and the president can't spend money not authorized by Congress.
SNELL: This constitutional fight is on the minds of a lot of lawmakers these days. They're starting to worry that Trump is taking executive power too far. It's not an entirely new concern. Republicans were upset when President Obama decided to go around Congress in 2014 in part to change deportation rules that created protections under the Deferred Action for Childhood Arrivals program, or DACA.
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BARACK OBAMA: I've got a pen, and I've got a phone. And I can use that pen to sign executive orders and take executive actions.
SNELL: And many Republicans, like Louisiana Senator John Kennedy, say Trump is just doing something similar. He's taking advantage of the laws as they stand today.
JOHN KENNEDY: Well, this power was given to the executive branch a long time ago. So the cow's out the barn.
SNELL: Republicans like Kennedy say the power Trump is using comes from the post-Watergate National Emergencies Act. For decades, the law was mostly used in urgent situations on issues where Congress generally agreed with the White House. Past presidents used it for things like imposing sanctions on foreign actors who violate international law or for natural disasters, terrorist attacks like 9/11 and health emergencies like the swine flu in 2009. But Thomas Mann, a senior fellow at the nonpartisan Brookings Institution, says what Trump's doing is different.
THOMAS MANN: Congress has already acted - that is, acted not to authorize the funds. Under those circumstances, it's hard to see how that could ever possibly be defended as a natural extension of what past presidents have done.
SNELL: And that bothers senators like Virginia Democrat Tim Kaine, who say Trump is just escalating a long and slippery history of presidential power grabs.
TIM KAINE: It isn't this president who started it. It's been a series of over decades Congress delegating way too much to the executive.
SNELL: Kaine says there are a lot of examples. In particular, he says Congress is failing to follow through on their own authority under the War Powers Act, which is supposed to require presidents to ask Congress to authorize military force. Presidents have largely ignored that requirement, and Congress hasn't done much about it. But now the Senate is planning a second bipartisan vote to end U.S. assistance for Saudi Arabia's intervention in the civil war in Yemen. And Kennedy says when it comes to national emergencies, Congress could just decide that it's time to reset the balance.
KENNEDY: To me, there are two issues. The first issue is, does the president have the authority? I think he does. The second issue is, should he have the authority? And I'm all for re-examining that.
SNELL: But that would require lawmakers and the president to agree that it's time for Congress to have more power. Kelsey Snell, NPR News, the Capitol. Transcript provided by NPR, Copyright NPR.