Barack Obama: “We must respond to it with seriousness of purpose, toughness, and strength.”

I think when you understand the complexities of America and the contradictions of America, I don’t think it makes you love it less. I think it makes you love it more.

Now the ball’s in your court, Iowa.

Every president here today, as different as we are, has tried our best to uphold the values that John McCain and Mitt Romney believed in no less than I did.

Your task is not to impose litmus tests.