If, technologically, it is possible to make an impenetrable device or system where the encryption is so strong that there's no key - there's no door at all - then how do we apprehend the child pornographer? How do we solve or disrupt a terrorist plot?

A lot of countries have advanced capabilities. And given the vulnerabilities of our infrastructure and our economies to digital platforms, we have to be careful in making sure that this doesn't become a lawless, low-level battlefield.

The market alone can't solve our health-care woes.

I use a different style if I'm speaking to a big crowd; I can gin up folks pretty well. But when I'm in these town hall settings, my job is not to throw them a lot of red meat. I want to give them a sense of my thought process.

That window is closing. . . . Now, the clock is ticking. . . . We're not going to have these talks just drag out in a stalling process. . . . We haven't given away anything - other than the opportunity for us to negotiate

There's nobody to guide through the process of becoming a man... to explain to them the meaning of manhood. And that's a recipe for disaster.

You have social media and the Internet and immigration and so, suddenly, cultures are clashing and people feel as if they're less familiar with the people around them. That causes social anxieties.