The use of the United States Marine Band for a de facto political rally, where guests donned “Make America Great Again” hats and “Blexit” T-shirts – backing a movement that urges Black Americans to exit the Democratic Party – marked another instance of the president pushing the boundaries of U.S. law and the military tradition of political neutrality.

The band has played at every presidential inauguration since 1801, when President Thomas Jefferson gave the group the title “The President’s Own,” according to its online history. The band is called upon when the president is discharging his duties as head of state.

But federal regulations bar the use of government resources for, and the coercion of federal employees into, political activities aimed at a candidate’s election – and taxpayer-funded military bands cannot be used for campaign events. Members of the U.S. military are prohibited from wearing military uniforms at political campaign events.