USO brings drinks, snacks and a ‘warm welcome’ to Guard troops at the Capitol USO mobile units with National Guard troops at US Capitol As more than 25,000 National Guard troops have been called in to help law enforcement with security surrounding the inauguration of President-elect Joe Biden, a familiar face has joined them: the USO. In three different locations near the U.S. Capitol, USO workers are on the ground with their mobile units providing a variety of grab-and-go snacks, coffee, drinks, and hygiene items for the troops when they have a break. As of Friday afternoon, they had provided items to around 12,000 troops, but that increased Friday night when they saw such a surge that the team was on the ground until 2 a.m., Sweeney said.