President Donald Trump speaks during an event in the Rose Garden at the White House to declare a national emergency in order to build a wall along the southern border, Friday, Feb. 15, 2019 in Washington. Credit: Pablo Martinez Monsivais | AP

President Donald Trump said Friday that he will declare a national emergency as a means to circumvent Congress and build additional border barriers. He is seeking to secure about $6.5 billion more in funding than Congress has approved.

“I’m going to be signing a national emergency,” Trump said in the White House Rose Garden. “We’re talking about an invasion of our country with drugs, with human traffickers, with all types of criminals and gangs.”

Trump also plans to sign spending legislation to avert a government shutdown, his chief of staff said.

Many of Trump’s Republican allies have called a national emergency ill-advised, and Democrats are promising immediate action aimed at blocking it. The declaration is expected to face an array of legal challenges, possibly including from congressional Democrats.

Friday’s announcement follows passage of a 1,169-page spending bill that provides $1.375 billion for 55 miles of new fences along the border in Texas, far short of the $5.7 billion Trump had sought for 234 miles of steel walls.

In a statement issued as Trump spoke, House Speaker Nancy Pelosi, D-California, and Senate Minority Leader Chuck Schumer, D-New York, called Trump’s emergency declaration “unlawful.”

“The President’s actions clearly violate the Congress’s exclusive power of the purse, which our Founders enshrined in the Constitution,” the statement said. “The Congress will defend our constitutional authorities in the Congress, in the Courts, and in the public, using every remedy available.”

“The President is not above the law,” the statement said. “The Congress cannot let the President shred the Constitution.”

All four members of Maine’s delegation voted for the spending bill to keep the federal government operating. But each expressed opposition to Trump’s proposal to declare an emergency.

U.S. Sen. Susan Collins, a Republican, said in a Thursday statement that Trump’s emergency declaration would be a “mistake” of “dubious constitutionality” that would be challenged in court. U.S. Sen. Angus King, an independent who caucuses with Democrats, said in a statement it is “antithetical to our American system of government.”

Maine’s two Democratic U.S. representatives also harshly criticized the move, with Chellie Pingree of the 1st District calling it an “abuse of power,” and Jared Golden of the 2nd District said lawmakers “should fix our immigration system and strengthen our borders with bipartisan deals like the compromise bill we’re voting on today.”

Trump acknowledged in his remarks that his declaration of a national emergency would face court challenges and that he could lose in lower courts.

“Hopefully we’ll get a fair shake” in the Supreme Court, Trump said. “We’re declaring it for virtual invasion purposes.”

He later added: “Sadly, we’ll be sued, and sadly, we’ll go through a process.”

As Trump was still speaking, New York Attorney General Letitia James, a Democrat, said the president had created a “constitutional crisis.”

“This action will harm Americans across the country by diverting funds necessary to handle real emergencies and real disasters to advance the President’s personal agenda,” James said in a statement. “We will not stand for this abuse of power and will fight back with every legal tool at our disposal.”

Before the announcement, White House acting chief of staff Mick Mulvaney told reporters the measures were necessary because Congress wouldn’t act.

“They are simply incapable of providing the amount of money necessary in the president’s eyes to address the current situation at the border,” he said.

The White House’s goal is to build more than 234 miles of new barriers. It will be a bollard-wall type structure, officials said, not the concrete wall Trump promised during his campaign.

BDN writer Michael Shepherd contributed to this report.

Erica Werner, Seung Min Kim and Rachael Bade contributed to this report.