President Donald Trump on Thursday defended his emergency declaration along the southern border shortly before an expected Senate vote to block it.

Trump has been fighting to secure funds for the construction of a wall along the southern border.

He made his emergency declaration after signing a compromise budget deal that failed to reach his requests for funding. The Senate is now prepared to vote and possibly pass a resolution to block the emergency declaration.

“Prominent legal scholars agree that our actions to address the National Emergency at the Southern Border and to protect the American people are both CONSTITUTIONAL and EXPRESSLY authorized by Congress,” Trump wrote on Twitter.

“If, at a later date, Congress wants to update the law, I will support those efforts, but today’s issue is BORDER SECURITY and Crime!!! Don’t vote with Pelosi!”

Related: House Dems Pass Resolution to Block Trump’s Border Emergency

Trump made the emergency declaration in order to free up billions of dollars in emergency funds for the border wall from various federal reserves through the National Emergencies Act (NEA).

He has repeatedly argued the situation at the border is a crisis and that a wall is critical to deterring illegal drugs and criminal gangs from coming into this country.

Senate Republicans are considering a separate bill that would restrict future emergency declarations. Sen. Mike Lee (R-Utah) introduced the measure to automatically end emergency declarations after 30 days unless they received congressional approval. Congress currently can cancel an emergency declaration but only by passing a resolution that could overcome a veto.

McConnell said in response to the bill that nearly everyone in his caucus agrees with the president about securing the border. But he admitted there is concern about the emergency declaration.

Who do you think would win the Presidency?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

He also stressed his caucus believes the president did nothing wrong under current law but that the law itself might need to change.

“A vote for today’s resolution by Republican senators is a vote for Nancy Pelosi, crime, and the open border Democrats!” Trump said in a later tweet.

Trump reluctantly signed the compromise deal to avoid a second partial government shutdown as a result of the dispute on February 15.

The proposal only included $1.375 billion for physical barriers. He had entertained the idea of declaring an emergency declaration for the weeks leading up to that point unless he got 5.7 billion to fund the border wall.

Rep. Joaquin Castro (D-Texas) introduced the resolution soon after the president made the declaration and it quickly gained support from party leaders.

The proposal blocks the president from diverting emergency funds for the construction of the border wall. The House already passed the resolution, mostly along party lines, on February 26.

Senate Republicans have a majority but there appeared to be enough defectors to aid in passage. Democrats only needed four lawmakers to cross party lines which they appear to have. There has generally been support among the party about securing the border, though using an emergency declaration to get the wall has been more divisive.

Trump told senators on Wednesday to use their discretion but also warned them against blocking his emergency declaration. He argued the vote is not about the constitutionality of the move because it is constitutional — rather, it’s a vote that comes down to border security.

He has also said he plans to veto the resolution if it comes to his desk.

Related: Dems Introduce Resolution to Block Trump’s Emergency Declaration

Trump is facing lawsuits for his emergency declaration, as he predicted he would be. California Attorney General Xavier Becerra is leading over a dozen other states that have sued the administration.

The American Civil Liberties Union (ACLU) became one of the first major organizations to announce a lawsuit soon after the president made his declaration.

Check out this video: