Our intelligence communities spend a lot of time and effort gathering a lot of strands and a lot of data [on Russian hacking]. There are times where they're very cautious and they say, "We think this is what happened, but we're not certain."

What I'm interested in doing after I get out of the presidency is to make sure that I'm working with that next generation so that they understand you can't just rely on inspiration.

I know that campaigns can seem small, and even silly. Trivial things become big distractions. Serious issues become sound bites. And the truth gets buried under an avalanche of money and advertising. If you're sick of hearing me approve this message, believe me - so am I.

We will respond to the threat of climate change

The law is a powerful thing but the law doesn't always change what's in people's hearts. And so all of us have an obligation to think about how we're treating other people.

I'm not going to Wall Street [after the presidency]. The amount of time that I'll be investing in issues is going to be high. But it'll be necessarily in a different capacity.

I remember having meetings with Republican senators who initially had been trying to engage [Obamacare] but saw that the politics of 'no' were growing inside the Republican Party.