President Trump kicked off Tuesday morning with a five-tweet discourse oscillating between praise for existing border security, calling for funding for his promised border wall, and blaming Democrats. He topped it off by promising he would simply use the military to build the wall: “If the Democrats do not give us the votes to secure our Country, the Military will build the remaining sections of the Wall.”



....People do not yet realize how much of the Wall, including really effective renovation, has already been built. If the Democrats do not give us the votes to secure our Country, the Military will build the remaining sections of the Wall. They know how important it is! — Donald J. Trump (@realDonaldTrump) December 11, 2018



The president is saying he's willing to circumvent Congress and use the military to get the policy he wants.

This isn’t the first time that the White House has floated this idea. Trump has previously said in April, “We’re going to have our wall, and we’re going to get it very strongly. The military’s going to be building some of it.” That statement was backed up by a request from the Department of Homeland Security to the Department of Defense to use $450 million to fund the wall in September.

But, having the military build a border wall is actually a much more complex process than Trump seems to think. Armed forces are not little army men that the White House can move at will — nor should they be.

For the military to take the lead on border security, authority would need to shift from the Department of Homeland Security to the Department of Defense. While that would allow the funding for the wall to come from the deeper DOD budget, doing so would likely require congressional approval.

Even if Secretary of Defense Jim Mattis wanted to used Pentagon funds for the wall, he would need to seek approval from Congress for a reprogramming request that would come at the expense of other military projects such as renovations at bases. The other option would be to try to include it as an item in defense appropriations, although that too would require approval from Congress.

Short of congressional approval, the White House could declare part of the proposed wall vital to national security, which would allow spending of up to $50 million a year. The other option would be for Trump to declare a national emergency, which would circumvent Congress but still pull money from the existing military construction budget — an unpopular move as it would take funds from districts that host military bases.

Although it’s true that DOD and the military have been involved in border security before — including the Army Corps of Engineers building border barriers — that has been in a supporting, rather than leading, role. Shifting the power of the military to take on what has typically been the role of law enforcement would be a fundamental change in how domestic issues are addressed.

Regardless of where you stand on the need for increased border security, the president looking to the military as a way to circumvent congressional approval should be deeply troubling as both undemocratic and authoritarian. Congress and the need for congressional approval of funds for national security projects are built into our democratic system. Tossing them out on the whim of a president bent on making good on a campaign promise undermines the system of checks and balances.