He will not. It's an empty threat, as are most of his.
Sooner or later that is what will be attempted, if not by Don, by his successors. The empire is in decline, review the history of the collapse of empires. Britain's was rather tame, I would not wager that ours shall be. Revisit the Patriot Act, then Obama made some pretty good progress on this trend as, well while Don is attacking civil and voting rights. OCCUPY, Ferguson and DAPL were war games, so is this border charade. Best keep your eye on the growth of for profit prisons with slave labor leasing and corporate state for profit internment camps, the militarization of the police, the mass surveillance state, the roll out of the military out into society for "safety", the fact that merely an accusation of "terrorist" with zero evidence is enough to get someone swept up, and the fact that the police are now able to murder unarmed non-threatening citizens with impunity.
We are one mass corporate state media suggested "terrorist" event or "national security threat" away from martial law and a majority of the masses lack the backbone to resist. Whites are by and large clueless, wrapped in a cocoon of belief that surely they will not come for them. Once deemed beneficial as a buffer between the aristocracy and "the other", we are all now "the other"; your labor is no longer required by the Wall Street/donor/"job creator" class for profit margin growth to infinity, that got outsourced while you were obediently engaged in mass consumption. These walls are for a return to neofeudalism.