I'm not able to go in with an act that I use month to month year to year all the time. It's constantly evolving and changing and that keeps me on my toes but certainly adds to the challenge.
Today I challenge our nation to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years.
As a matter of fact, it's in our interests that we help reformers across the Middle East achieve their objectives. This is the fundamental challenge of the 21st century.
One of the things I learned as president is that your life is just not going to unfold the way you want it to. There will be surprises, challenges, and therefore the question is how you deal with the unexpected.
For we have always understood that when times change, so must we, that fidelity to our founding principles requires new responses to new challenges, that preserving our individual freedoms ultimately requires collective action.