Easy. Tell Mexico to do it using their own police or military, or we will cut subsidies to them in a million ways. Or impose immediate confiscatory tariffs on their goods. Or end tourist travel to Mexico. Pick one. All of these are justified if the threat is so serious that it warrants deploying 15,000 soldiers to the Texas border, unless the President is lying about the threat.
Any competent tactician would address the threat before it arrives at the border and creates a crisis. But that’s just it - it isn’t a real threat. Although there may be a bedraggled horde that’s half made up of women and children, it’s a migrant and refugee horde. It’s not a group of “invaders” of criminals and rapists. But that’s what Trump wants you to think, because its an easy way to manipulate you. You prove you’re gullible and manipulated by a dime store con man every time you post about this.