For Trump supporters who advocate an immigration crackdown, the Sunday's events showed migrants storming a protected border, confirming fears of an "invasion" of migrants defying U.S. laws.
In fact: 5,000+ Central American migrants have reached Tijuana, as part of the caravan that traveled some 3,000 miles. Most are from Honduras, where gang violence is widespread and a 2009 coup triggered an ongoing political crisis. The U.S. has long played a key role in Honduran politics.
Lethal force decisions are limited to protecting federal agents — and at the discretion of the secretary of defense. Mattis, in a briefing last week, said that the Department of Homeland Security has issued no call for lethal force. ACLU in an interview with NPR: "because that's part of the legal analysis, whether the asylum seekers will be safe in Mexico, we can't imagine any proposal will be legal."