I've often said that the best thing to come out of Trump's presidency won't be any particular piece of legislation passed, however good some of them may be. Rather, his biggest achievement is challenging what can and can't be discussed and debated in the political mainstream. Until Trump's candidacy and election, "debate" on immigration among Republicans was about one-upping the Democrats on amnesty and increases in legal immigration quotas. Trump has actually put restrictions on immigration back on the bargaining table, whereas before these views were relegated to the "extremist" fringe by so-called "respectable" politicians and media alike.