I read a ton of paper every day. I read the newspapers, I read my intelligence materials, I read all the briefing materials. I read the newspaper in hard copy.

You can't sit on the sidelines and read your iPhone and be on social media and expect everything to be cool. You have to be part of this.

We must be honest in acknowledging that neither Germany nor the US has the luxury of assuming that we can skate by on half-measures in Afghanistan and Pakistan and not risk suffering the consequences.

We have to know who we are and know what we believe.

For the United States to recommit itself to the obligation that we undertook in the Nuclear Non-Proliferation Treaty that many other states undertook, which was to work towards disarmament and the eventual elimination of nuclear weapons, is something that manifestly serves our national security interests.

If you're trying to get something done, there will always be people who don't want to see you get something done, or who have a stake in the status quo. And if they approach that through ad hominem criticism of you, you've got to have enough confidence and thickness of skin to be able to endure.

It is manifestly in the interest of the United States to deal with the very real threat that climate change poses. And that's why President Obama has worked so hard to reduce our own emissions and to lead internationally in forging the Paris climate agreement.