The aides drafted the proclamation on June 1, 2020, during a heated debate inside the administration over how to respond to the protests. Mr. Trump, enraged by the demonstrations, had told the attorney general, William P. Barr, the defense secretary, Mark T. Esper, and the chairman of the Joint Chiefs of staff, Gen. Mark A. Milley, that he wanted thousands of active-duty troops on the streets of the nation’s capital, one of the officials said. Mr. Trump was talked out of the plan by the three officials. But a separate group of White House staff members wanted to leave open the option for Mr. Trump to invoke the Insurrection Act to call in the military to patrol the streets of the capital. They decided it would be prudent to have the necessary document vetted and ready in case the unrest in Washington worsened or the city’s mayor, Muriel Bowser, declined to take measures such as a citywide curfew, which she ultimately put in place.