What did I tell you? Next step was to begin controlling the movement of people into and out and around DC. Taking over the largest mass transit hub in the city is the first step to doing so.

Proof it has nothing to do with crime? This is the best they could come up with for justification:

Vance, a former senator, had complained about an incident where someone yelled at his son while walking through Union Station a couple of years ago. But with the arrival of National Guard troops, he said the station was safe for parents to bring their children.