He did offer complete candor.

I believe my record as president, my leadership in the world, my vision for America’s future all merited a second term, but nothing, nothing can come in the way of saving our democracy, and that includes personal ambition.

He still thinks he’s perfectly capable of being an excellent president. But the voters disagree, and he’s stepping down to give us the best chance of stopping Trump.

I’m sure you don’t like his answer, but that’s his answer.