If 45 bans assault weapons I fear its over and cabal wins.
BOHICA.
President Trump, unlike a couple recent Presidents, seems to highly value both the Constitution and the 2nd Amendment. So, I don't believe he would ever do this.
The power of the President does not include the power to "ban assault weapons", anymore than it does to ban cars.
If Trump were to attempt this then I believe his political support would crumble and there is no way he could win a second term.