A shrewd political tactic (credit to Trump). I think that crash is overdue and is coming no matter who wins the US presidency. If he isn't re-elected, it will be easy for him to point the finger. If he is re-elected, well then it doesn't matter to him because he already has what he wanted.

Trump makes bold economic moves. They may pay off, but they are risky. Ultimately the economy will crash, but it won't be his doing: it will be the result of a decades long string of errors all cumulating and coming home to roost. Sooner or later the piper has to be paid.