I'll be honest with you, I don't agree with President Obama about everything. But I've gotten to know him, I've worked with him, and the choice is crystal clear.

I was a Republican and I saw the activists and what they were doing, it was intolerable to me.

Half a century ago, Ronald Reagan, the man whose relentless optimism inspired me to enter politics, famously said that he didn't leave the Democratic Party; the party left him. I can certainly relate. I didn't leave the Republican Party; it left me.

It's more important to promote a culture of life. What I mean by that is that I believe what we need to do is not change the law, but change hearts.

DiCaprio left the party with 20 women? I did that in 2012!

As a former lifelong Republican, it pains me to tell you that today's Republicans - and their standard-bearers, Mitt Romney and Paul Ryan - just aren't up to the task. They're beholden to 'my way or the highway' bullies, indebted to billionaires who bankroll ads and allergic to the very idea of compromise.

I've decided to do it, for the pure and simple reason that I just think it's the right thing to do.