WASHINGTON—On Jan. 6, supporters of President Donald Trump gathered in the nation’s capital for a demonstration, called the “Save America March.” The plan was to hold a rally in The President’s Park just south of the White House and then march to the Capitol building to demand that Congress and Vice President Mike Pence reject electoral votes for former Vice President Joe Biden from states where election results were marred by irregularities, allegations of fraud, and unconstitutional voting rule changes. By the end of the day, the Capitol went through several rounds of lockdown after a sizable group of protesters broke inside. Four people died in or around the Capitol, including Ashli Babbitt, a woman who was shot dead by a Capitol Police officer. Three others died due to medical emergencies, authorities said. One man died of a heart attack and another of a stroke, and one woman was crushed …