Trump didn’t cave. The GOP caved. He’s got two choices: Open the government himself or have his veto overridden. In either case no wall. He has determined publicly splitting with his own party will be a wedge the Dems use to weaken him further. He has all the facts. We don’t. So I’ll give him the benefit of the doubt.
We all know the pubbies in the Senate are spineless Jelly fish. There should never have been a shut down if we didn't have Party backing for the long haul. This was just a huge waste of time and the President comes off looking weak because of it.
This reminds me a lot of the “extra week to investigate Kavanaugh” deal. Vote was imminent but was in danger due to flaky Republicans. Forcing a vote would have meant defeat. Squishy pubs made a deal w the Dems to delay the vote for a week to further vet Kavanaugh. Lindsay Graham and even Trump calmly supported it as the base howled (myself included, wrongly)..Dems win blah blah
Similarly here Trump is going along with the compromise-delay. It placates squishy Pubs and reinforces support of his long term goal for a short term sacrifice.
And just like Kavanaugh eventually was confirmed so too will Trump get his way on border security.