>In 1967, Miami police Chief Walter Headley used the phrase "when the looting starts, the shooting starts" during hearings about crime in the Florida city, invoking angry reactions from civil rights leaders, according to a news report at the time.

> Segregationist presidential candidate George Wallace also used the phrase during the 1968 campaign.

While you might like to believe that the phrase could mean anything, it certainly doesn't. And in the context of Trumps tweet, which specifically mentions the military, it certainly means that he was threatening to have the US military fire on US civilians.

Now consider that in the context of the US threatening action against China using "tough" tactics to subdue protests in Hong Kong and you'll see the tweet for what it is. The same kind of rhetoric and threat of violence against protesters that the US condemns elsewhere in the world.