President Obama visits Jacksonville Naval Air Station

An excerpt from his speech to 3,000 military, mostly sailors and Marines:

"We're reminded of this again with today's helicopter crashes in Afghanistan. Fourteen Americans gave their lives. And our prayers are with these service members, their civilian colleagues, and the families who loved them.

And while no words can ease the ache in their hearts today, may they find some comfort in knowing this: Like all those who give their lives in service to America, they were doing their duty and they were doing this nation proud.

They were willing to risk their lives, in this case, to prevent Afghanistan from once again becoming a safe haven for al Qaeda and its extremist allies. And today, they gave their lives, that last full measure of devotion, to protect ours.

Now, it is our duty as a nation to keep their memory alive in our hearts and to carry on their work. To take care of their families. To keep our country safe. To stand up for the values we hold dear and the freedom they defended. That's what they dedicated their lives to. And that is what we must do as well.

So I say to you and all who serve: Of all the privileges I have as President, I have no greater honor than serving as your Commander-in-Chief. You inspire me. And I'm here today to deliver a simple message -- a message of thanks to you and your families.

Being here, you join a long, unbroken line of service at Jacksonville -- from the naval aviators from World War II to Korea to Vietnam, among them a great patriot named John McCain. You embody that sailor's creed, the "spirit of the Navy and all who have gone before" -- Honor, Courage, Commitment.

In recent years, you've been tested like never before. We're a country of more than 300 million Americans, but less than 1 percent wears the uniform. And that 1 percent -- you and those in uniform -- bear the overwhelming burden of our security."