By Rebecca Ballhaus and Kristina Peterson 

WASHINGTON -- President Trump declared a national emergency to bolster his border-wall plans, supplementing the barrier funding contained in a spending bill he plans to sign with billions in additional funds diverted from elsewhere in the government.

The moves -- designed to pull together $8 billion in funding for border barriers -- stave off a second government shutdown but have ignited a new battle over the legality of his border-spending ambitions.

Speaking in the Rose Garden, Mr. Trump said a border wall was key to national security. "We're talking about an invasion of our country," he said.

The House approved the spending bill late Thursday, hours after its passage in the Senate, sending the legislation to the president's desk. Mr. Trump planned to sign the bill after his remarks.

The $333 billion package of seven spending bills includes $1.38 billion in funding for 55 new miles of physical barriers -- far less than the $5.7 billion Mr. Trump had asked for to fund 234 miles of new barriers.

The president's push for $5.7 billion in border-wall funding led to the five-week government shutdown, the longest in U.S. history, that ended last month.

Mr. Trump, in lengthy remarks on the courts system, said he expected to be sued over his emergency declaration. "We will possibly get a bad ruling. And then we'll get another bad ruling. And then we'll end up in the Supreme Court, and hopefully we'll get a fair shake," he said.

He also suggested he didn't need the full $8 billion his administration is seeking to build the wall. "So we have a chance of getting close to $8 billion," he said. "Whether it's $8 billion, $2 billion or $1.5 billion, it's going to build a lot of wall."

Mr. Trump voiced frustration with the resistance to funding a border wall and sought to play down the drama of his declaration, noting that emergency declarations had been put in place before. He added: "There's rarely been a problem. They sign it, nobody cares." Previous presidents have signed emergency declarations, but not to fund initiatives that Congress declined to fund.

In addition to the wall funds in the spending bill, White House acting chief of staff Mick Mulvaney said Friday that the president will seek to divert about $6.7 billion from elsewhere in the government to build 234 miles of steel bollard wall -- a move that is certain to invite court challenges. Mr. Mulvaney said the president was taking executive action because Congress had proved "simply incapable" of allowing the level of wall funding Mr. Trump had demanded.

Included in that will be $2.5 billion that Mr. Trump will divert from the Department of Defense's counter-drug efforts, $600 million from the Treasury Forfeiture Fund and $3.6 billion from military construction efforts, Mr. Mulvaney said. The latter bucket of funds can only be accessed through an emergency declaration.

A senior administration official said the White House was still reviewing which military construction projects would be affected by the emergency declaration and would seek to target projects repairing facilities that "might be able to wait a couple of months into next year."

Senate Majority Leader Mitch McConnell (R., Ky.), who spoke with the president Thursday, said he would support his declaration. But the plan was met with swift criticism from other lawmakers in both parties. Democrats said they would challenge any efforts to move money around without congressional approval, including possibly filing a lawsuit.

Rep. Jerrold Nadler (D., N.Y.), chairman of the House Judiciary Committee, said he would support a resolution to terminate an emergency declaration and that he intends to "pursue all other available legal options."

Republican lawmakers also criticized the president's plan, saying it undermined Congress and set a dangerous precedent if future Democratic presidents sought to declare emergencies over their priorities, such as climate change.

"I don't think that this is a matter that should be declared a national emergency," Sen. Lisa Murkowski (R., Alaska) said.

Hundreds of people or organizations -- including advocacy groups like the American Civil Liberties Union and landowners along the Mexican border -- could also potentially claim harm from the emergency declaration, allowing them to sue. If funds were diverted from civil-engineering programs intended to protect against floods or wildfires, for instance, states and local governments that stand to benefit from those projects potentially could challenge the reappropriation as unlawful.

Federal law doesn't define an emergency. The first formal emergency proclamation was issued by President Wilson in 1917, limiting the transfer of U.S.-owned ships to foreigners during World War I, according to a report by the Congressional Research Service.

There are currently 30 national emergencies in effect, according to the service, including those related to the Sept. 11, 2001, terrorist attacks and the Iraq war. President George W. Bush declared 13 national emergencies, and President Obama declared 12.

In the 1970s, Congress became worried about the expansion of power and passed the National Emergencies Act, a bipartisan measure that placed limits on presidential discretion. Among other provisions, it allows Congress to terminate an emergency declaration, and it automatically ends an emergency after 180 days unless the president renews it.

Funding for many government agencies was set to expire at 12:01 a.m. Saturday unless Congress passed the spending legislation and Mr. Trump signed it into law. The seven-bill package would fund the government for the rest of the fiscal year, which runs through September.

The congressional spending package restricts where the administration can build, ruling out several federal areas including the Santa Ana National Wildlife Refuge and National Butterfly Center, where the government would face fewer legal challenges to building than it would on private land, but where local opposition is still steep. A senior administration official said Friday that the White House considers the congressional restrictions only to apply to the $1.375 billion appropriated in that spending package, and that the other $6.625 billion could be used without those restrictions.

Top administration officials haven't said where they want to locate the 234 miles of new barriers, how they have arrived at that number, or whether the miles would extend the length of the wall by adding barriers where there are none currently or reinforce existing barriers. About 654 miles of the current border have some kind of physical barrier, though only about 78% of that barrier was considered to be modern, effective designs ahead of Mr. Trump taking office.

Much of the rest of the border has natural barriers, and in the past Mr. Trump has said that only about 700 miles of barriers might be needed to secure the border. On Friday, the administration declined to describe the plans for the wall in any detail.

Write to Rebecca Ballhaus at Rebecca.Ballhaus@wsj.com and Kristina Peterson at kristina.peterson@wsj.com

(END) Dow Jones Newswires

February 15, 2019 12:52 ET (17:52 GMT)