Until we fully understand what turned two brothers who allegedly perpetrated the Boston Marathon bombings into murderers, it is hard to make any policy recommendation other than this: We need to redouble our efforts to make America stronger and healthier so it remains a vibrant counterexample to whatever bigoted ideology may have gripped these young men....And the best place to start is with a carbon tax.

Remember, the difference between the world frozen over, in an ice ball, and the warming period we're in now is just 6 degrees centigrade. A change of just 1 degree can have a huge effect.

I have a daughter who is a sophomore in college and another who is in the 11th grade of high school.

Obviously China is clearly taking the lead in some areas, but when it comes to the most advanced innovation, it's still America.

Until we fully understand what turned two brothers who allegedly perpetrated the Boston Marathon bombings into murderers, it is hard to make any policy recommendation other than this: We need to redouble our efforts to make America stronger and healthier so it remains a vibrant counterexample to whatever bigoted ideology may have gripped these young men....And the best place to start is with a carbon tax.

Water is our next great environmental challenge. It is the new oil. How are we going to preserve this sport unless we are designing and maintaining golf courses that are energy net zero, carbon net zero and water net zero? Or ideally, energy positive, carbon positive and water positive, where they are taking out more than they are using.

I am being very humble about the Arab Spring. There's kind of a competition out there, you might have noticed, of who can be the first to say the Arab Spring is going to fail. Everyone says, "I told you so, I told you so about the Muslim Brotherhood." I have no desire to tell anyone anything. I don't know. I'm just listening, watching. It may turn out all these people are right, they may be wrong. They may be right this year and wrong next year, by the way. I'm just trying to listen day to day, figure it out.