National emergency

Updated at 4:56 p.m. ET

President Trump used his veto pen for the first time Friday, after Congress tried to reverse his national emergency declaration and rein in spending on a wall along the U.S.-Mexico border.

Congressional critics do not appear to have the votes to override Trump's veto. So, as a practical matter, the administration can continue to spend billions of dollars more on border barriers than lawmakers authorized, unless and until the courts intervene.

Updated at 4:16 p.m. ET

The Republican-controlled Senate approved a resolution to terminate President Trump's national emergency declaration at the U.S.-Mexico border, putting Congress on a path to its first veto confrontation with the Trump administration.

Senator Rand Paul of Kentucky says he'll vote in favor of a resolution to terminate President Trump's national emergency declaration with regards to the U.S.-Mexico border. Paul's support means the resolution will likely pass the Senate with bipartisan support and could force the president to issue his first veto.

Paul's announcement, coming from an-otherwise close ally of the president, lays bare the discomfort many Republicans have had with the emergency declaration.

Updated at 5:15 p.m. ET

The White House is working to identify federal dollars that could be redirected to construct a border wall, if President Trump invokes his emergency powers to do so.

Updated at 5:20 p.m. ET

President Trump says he is willing to declare a national emergency if Democrats don't go along with his demands for $5.7 billion for a border wall.

Trump's campaign for a border wall took him to McAllen, Texas, on Thursday for a visit to a Border Patrol station and a roundtable discussion with local officials, before heading to the Rio Grande.