I can only hope this hurts them in 2018. BIGLY. Especially since they keep throwing out a figure of 11 - 15 Billion when experts have almost DOUBLED that. And that's just for the CONSTRUCTION, and not Year over year costs.
meanwhile america's roads, bridges, electrical/water systems/etc. lay crumbling. CLEARLY building a wall is the upmost of importance, especially in a day where illegal immigration from Mexico is at the lowest it has been in a long, long time.
The GOP majority isn't THAT huge and there are almost certainly enough that oppose wasting $15b on Donald Trump's vanity projects that they won't have the votes.
If they really wanted to push this through, this would have to be a hill they'd be willing to die on. I don't see that.
Even assuming, for the sake of argument, that they passed a spending bill on it, the chance they'd actually break ground on building such a thing within the next 10 years is extremely low - it would get bogged down in lawsuits, Trump being impeached, etc.
Can't there be like a referendum for people to vote on whether their money goes on a wall? Although given how recent referendums have gone, maybe that's a bad idea. "We won Mexwall, get over it" would appear in minutes.