WASHINGTON, D. C. - Ohio Republican Rob Portman is among a group of Senate Republicans who have co-sponsored a controversial measure that would leave President Donald Trump’s current presidential emergency intact but automatically end future presidential emergency declarations after 30 days unless Congress extends them.

Critics of the legislation say it was introduced Tuesday to provide political cover for Republicans who have constitutional concerns about Trump’s border emergency declaration but who don’t want to publicly rebuke him by supporting a House-passed measure that would overturn it.

“Republican Senators are proposing new legislation to allow the President to violate the Constitution just this once in order to give themselves cover," said a statement from House Speaker Nancy Pelosi, a California Democrat. "The House will not take up this legislation to give President Trump a pass.”

Portman is among a group of Republicans who support Trump’s border security measures, but worry the emergency declaration he made to secure money to build a wall on the nation’s southern border sets a bad precedent because Congress is supposed to make funding decisions. Portman hasn’t said how he’ll vote Thursday when the House resolution comes before the Senate.

On Tuesday, Portman was among a group of Republicans who discussed the matter with Vice President Mike Pence. After that meeting, one of the four Republican senators who previously backed the House resolution - North Carolina’s Thom Tillis - said a deal to revise the National Emergencies Act could change his stance.

To win Senate approval, the House resolution needs four Republican votes along with those of all its Democrats. Other Republican senators who back the resolution are Alaska’s Lisa Murkowski, Maine’s Susan Collins and Kentucky’s Rand Paul.

The author of the bill that would affect future emergency declarations, Utah Republican Mike Lee, said it would take back legislative powers that Congress gave away when it passed the National Emergencies Act of 1976. Current law requires Congress to pass a resolution of disapproval to block emergency declarations it deems inappropriate.

“If Congress is troubled by recent emergency declarations made pursuant to the National Emergencies Act, they only have themselves to blame,” said a statement from Lee. “If we don’t want our president acting like a king we need to start taking back the legislative powers that allow him to do so."

Portman spokeswoman Emily Benavides said her boss backs the bill because he "supports narrowing the scope of the National Emergencies Act so that Congress will have more control over these decisions in the future.”

She said he had a “robust discussion” about the emergency declaration with Pence on Tuesday, and will decide how to vote on the resolution to overturn it before Thursday’s vote.

Ohio Democratic Sen. Sherrod Brown called Lee’s bill a typical Republican tactic to “show no backbone when it comes to standing up to this President,” in keeping with to their failure to “stand up” to Trump when he made racist comments, shut down the government and declared "an emergency over something that’s not an emergency.”

“They are looking for an opportunity to look like they’re independent, but they’re not addressing this issue right now of the President’s emergency ,” said Brown.

Brown said he doesn’t object to finding a “long term answer,” to keep presidents from declaring emergencies in non-emergency situations, but said he didn’t know of any cases where past presidents abused the law.

“If they really want to take a stand, they’ll vote for the resolution tomorrow and then they’ll override the president’s veto," said Brown. “Then we’re all very glad to work for a long-term solution.”