Move ignites new battle over legality of border-spending ambitions.

President Trump was set to sign a spending bill that keeps the government open and lay out his plans to divert funds to build a wall on the southern U.S. border, including the declaration of a national emergency.

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.

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.

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