Let’s not give Pence more credit than he deserves. Pence didn’t decline to support Trump out of a sense of duty or because he cares about Americans, but because Dan Quayle (!) told him he had no choice in the matter:

Over and over, Pence asked if there was anything he could do.

‘Mike, you have no flexibility on this. None. Zero. Forget it. Put it away,’ Quayle told him.

Pence pressed again.

‘You don’t know the position I’m in,’ he said, according to the authors.

‘I do know the position you’re in,’ Quayle responded. ‘I also know what the law is. You listen to the parliamentarian. That’s all you do. You have no power.’

source: How Dan Quayle saved democracy. Yes, really.