For Trump, it's a useful distraction from Mueller, not a policy.
His presidency is falling apart. He can't get anyone to work for him. Everyone sees that their reputation will be ruined by association.
Now the Republicans know he is toxic in the voting booth they will be trying to figure how to wake up his base.
McConnell has decided to let Trump deal with his own government shutdown problem. I am sure he knows Pelosi has all the cards. Trump losing on the wall will be one nail in his coffin.