Okay, he spent too much. But here were his choices:
Give Democrats nearly everything they want, and Trump gets what he wants causing the debt.
Don't give Democrats anything, they shut down the government, and we don't get anything we want either.
So nobody gets anything, the government is shutdown for God knows how long, and it's a game of chicken the MSM is sure to blame Republicans for.
People get pissed, throw the Republicans out of leadership of Congress, the Democrats take over, and propose an even higher spending bill where they get everything and we get nothing. Trump is forced to sign it, or lose the White House in 20.