On Monday, protesters attempted to topple a statue of President Andrew Jackson in a park next to the White House, though police in riot gear intervened and stopped them. That night, Trump tweeted his dismay, and the next morning he wrote that he had “authorized the Federal Government to arrest anyone who vandalizes or destroys any monument, statue or other such Federal property in the U.S. with up to 10 years in prison, per the Veteran’s Memorial Preservation Act, or such other laws that may be pertinent.....”

Earlier Wednesday, defense officials said that the Army activated about 400 unarmed members of the Washington, D.C., National Guard to “prevent any defacing or destruction” of monuments.

Jackson, a former general in the U.S. Army, was known for his harsh treatment of Native Americans as president. He signed the Indian Removal Act, which led to the relocations of thousands of Native Americans and the deaths of thousands more.

Across the country, protesters have toppled statues of figures from America’s sordid past — including Confederate generals — as part of demonstrations against racism and police violence. Some attempts have grown heated; in New Mexico, a man was shot and wounded in a demonstration to tear down a monument to Spanish conquistador Juan de Oñate, a 16th-century despot who massacred indigenous people. The protest grew contentious after an armed militia group showed up at the scene.