You can't have it both ways....either it was something he HAD TO do, or it's meaningless. It can't be both.
It's meaningless BECAUSE he had to do it.
He said he'd endorse the nominee. No matter who. What does that endorsement mean? It means that the guy he endorsed was the nominee. He didn't say he'd endorse the nominee if he liked him. He said he'd endorse the nominee.
There was a fairly recent movie in which guy 1 is holding a gun on guy 2 and he's telling guy 2 to apologize. Guy 2 tells guy 1 something like "are you sure this is the type of apology you want, you're holding a gun on me."
In this case, the apology is Meaningless, because he Had To do it, by the guy with the gun.