The Pentagon announced late Monday that it would reallocate $1 billion in existing funds to pay for the construction of part of a barrier along the border with Mexico. This construction is "in support of the February 15 national emergency declaration on the southern border of the United States."

How much of the wall will this pay for?

According to a notification the Pentagon sent to Congress, this will pay for 57 miles of "18-foot-high pedestrian fencing."

It "gives the Department of Defense the authority to construct roads and fences and to install lighting to block drug-smuggling corridors across international boundaries of the United States in support of counter-narcotic activities of Federal law enforcement agencies."

Where did the money come from?

Congress had already approved this $1 billion for the Pentagon. In September, Trump signed a $674 billion appropriations bill to fund the Pentagon, including money for the purchase of new ships, fighter jets, and increased troop levels.

After a February spending bill failed to include the money for a border barrier that Trump had demanded, the president declared a national emergency in order to reallocate $6 billion from various existing programs to pay for the wall. Twelve Republicans in the Senate joined with Democrats in an effort to block this national emergency declaration. However, they did not garner enough votes to overturn a presidential veto.

Senate Democrats objected to the move

In a letter to acting Secretary of Defense Patrick Shanahan, 10 Democratic senators objected to the funding transfer. The letter stated, "The $1 billion reprogramming that the Department is implementing without congressional approval constitutes dollar-for-dollar theft from other readiness needs of our Armed Forces."

The senators then listed "substantial shortfalls" in the budgets of the Air Force, Marine Corps, and Navy, which they said "currently total $5 billion." The $1 billion for the wall, the senators argued, should go toward fixing these existing issues.