At least three Republicans have come out in opposition to President Donald Trump's decision to invoke national emergency power to secure border wall funding.

Sen. Thom Tillis wrote an opinion piece in the Washington Post, scrutinizing Trump's decision. He also reminded his colleagues that he opposed similar declarations made by former President Barack Obama.

From the perspective of the chief executive, I can understand why the president would assert his powers with the emergency declaration to implement his policy agenda. After all, nearly every president in the modern era has similarly pushed the boundaries of presidential power, many with the helping hand of Congress. In fact, if I were the leader of the Constitution’s Article II branch, I would probably declare an emergency and use all the tools at my disposal as well. But I am not. I am a member of the Senate, and I have grave concerns when our institution looks the other way at the expense of weakening Congress’s power. ... There is no intellectual honesty in now turning around and arguing that there’s an imaginary asterisk attached to executive overreach — that it’s acceptable for my party but not thy party.

According to Tillis, the GOP will suffer when the Democrats take over the White House again. They can then cite President Trump's declaration as precedent for the liberal policies.

"As a U.S. senator, I cannot justify providing the executive with more ways to bypass Congress. As a conservative, I cannot endorse a precedent that I know future left-wing presidents will exploit to advance radical policies that will erode economic and individual freedoms," Tillis wrote in his OpEd.

Sen. Lisa Murkowksi (R-AK) on Tuesday said she would vote to overturn the president's declaration, The Hill reported.

"When I say probably, I want to make sure that what in fact we are voting on when it comes to the Senate is what I believe it is. If it's what I have seen right now, I will support the resolution to disapprove," Murkowski told KTUU late last week.

Last week, Sen. Susan Collins (R-ME) said she doesn't support the president's decision to invoke a national emergency, CNN reported.

"I disagree with the President's decision to invoke the National Emergencies Act. I don't think that is what the law was intended for. It was intended for catastrophic events, such as the attacks on our nation on 9/11 and severe natural disasters," Collins said in an event in Maine. "I do support the lawsuit that was filed by the states. I think that may be the quickest way to get an injunction that would halt this transfer of funds."

House Democrats are expected to pass their resolution to block Trump's emergency declaration. They need 218 votes but already have 222 bill co-sponsors.

Democrats in the Senate, need all of their members, plus four Republicans, to vote together to overturn the declaration. With Sens. Tillis, Murkowski and Collins on their side, Democrats only need one more vote for the Declaration to get overturned.