In the scenario Hill Republicans fear most, Trump declares a national emergency and House Democrats quickly pass a joint resolution against it, sending what amounts to a political grenade into the Senate. There, Republicans would be forced into either supporting a national emergency or rebuking a GOP president on his signature issue.
It would also force them to grapple with a handful of other thorny issues – from executive overreach to separation of powers to raiding Pentagon money to pay for border security.
Sounds good to me.