A statement from McCain:

Today in Iraq, America and our allies stand on the precipice of winning a major victory against radical Islamic extremism. The security gains over the past year have been dramatic and undeniable. Al Qaeda and Shia extremists -- with support from external powers such as Iran -- are on the run but not defeated. Tough fighting remains ahead, especially in places like Mosul. Important political gains have also been made, but far more must be done in coming months to cement the gains made in huge cost in American blood and treasure.

Americans should be proud that they led the way in removing a vicious, predatory dictator and opening the possibility of a free and stable Iraq. Americans should be proud that once we implemented the surge and new counterinsurgency strategy, a dire situation has been dramatically improved. And, Americans know that the consequences of failure would leave our nation less secure for generations to come.

And from a speech Obama gave today:

It is time to have a debate with John McCain about the future of our national security. And the way to win that debate is not to compete with John McCain over who has more experience in Washington, because that's a contest that he'll win. The way to win a debate with John McCain is not to talk, and act, and vote like him on national security, because then we all lose.

The way to win that debate and to keep America safe is to offer a clear contrast, and that's what I will do when I am the nominee of the Democratic Party -- because since before this war in Iraq began, I have made different judgments, I have a different vision, and I will offer a clean break from the failed policies and politics of the past.