WASHINGTON, DC (Circa) - President Trump wants to fulfill a campaign promise to secure the southern border by guarding it with military personnel, but he could be hampered by legal issues and classic Washington politics.
Trump serves as commander-in-chief of all U.S. armed forces, giving him the final say on military matters. But like any government official, federal law limits what he can do in that capacity.
"It would be against the law, for example, to deploy active duty military troops to patrol the border, except in cases where we are actually being invaded, like a war," explained Theresa Cardinal Brown, the Bipartisan Policy Center's director of immigration and cross-border policy, in an interview. "Immigration enforcement, which is what the president is calling for is a civil enforcement action, and a law enforcement action, so they could not under law be deployed in that way."
The Posse Comitatus Act of 1878 formally restricted how the military could be utilized in domestic situations. It was passed in response to concern from former Confederate states regarding military occupation following the Civil War.
But there are certain exceptions. The National Guard has more latitude when it comes to domestic operations, as they are run by state governments. That said, the president has the authority to federalize the guard. Department of Homeland Security Secretary Kirstjen Nielsen announced Tuesday that the administration hopes to deploy guardsmen to the border "immeditely." Both Presidents George W. Bush and Barack Obama utilized National Guard troops along the border during their tenures, explained Brown, who served as a policy advisor to U.S. Customs and Border Patrol. That said, in those examples troops served in limited support roles.
Trump has also reportedly explored the possibility of utilizing the military to construct his promised border wall. Congress has provided only $1.6 billion in funding for the wall, despite Trump's request for $25 billion. Trump hopes to use the Department of Defense budget to get the wall built, but that could also face some legal and political challenges.
"Congress protects its prerogatives on appropriations so closely. And a lot of the military funding for building, for example, is scheduled for specific congressional districts," said Brown. "So I think there's a political issue there."
Congress has the power of the purse when it comes to government spending, which it spells out specifically in appropriations. That means the president can't simply take funding from one program and put it towards another.
After a long and arduous process, Congress was finally able to pass a bill to fund the government last month. Appetite for an additional spending bill for more border funding could be limited, as sights are set on preparations for the next fiscal year.