My departure from the presidential race was the most difficult decision I've ever made, but I'm convinced it was the right one. As I said when I announced my decision, there is a time to stay and a time to fold; a time to know when to leave the stage.

Although this is a moment of disappointment, I am very grateful: grateful to the thousands of Americans who have given their time, their energy, and financial and prayerful support; grateful to the old friends who have stood by us and to the new friends we've made throughout the country. For both Marilyn and myself, our supporters have made this a tremendous, uplifting experience from day one.

This is the end of a campaign, not a cause. I am going to stay in the arena. As John Adams said, our obligations to our country cease only with our lives. I am still young, fortunate to have plenty of stamina and good health, and blessed with a loving family and friends across America. I called my latest book Worth Fighting For because our values, our ideals, our country are worth fighting for. That's exactly what I'm going to do. Please keep in touch, and I'll see you again.

Sincerely,