A broken promise is a lie. Does something good change a lie? Seriously, do you tell your kids that? Does you spouse dismiss a lie that way?
As long as Trump doesn’t go the Reagan disaster then I am cool. Reagan the only president to give straight up amnesty to millions only to make the problem worse.
After you jump down from the moral high ground you might have a gander at pragmatic.
In other words, what you advocate might be right, but holding that position might actually find you reversing progress. Do you want to go in the other direction?