JUDY WOODRUFF: John McCain entered the fray while traveling on his campaign bus yesterday and again today, referring to a previous statement from Obama that he would be willing to talk with Iran's president, Mahmoud Ahmadinejad.SEN. JOHN MCCAIN (R), Arizona: Senator Obama wants to have direct talks with the president of Iran, who has said that Israel is a stinking corpse and who wants to wipe Israel off the map -- those are his words, not mine -- and that are developing nuclear weapons, that are exporting the most lethal, explosive devices into Iraq, killing innocent Americans. I strongly disagree with that.
JUDY WOODRUFF: Today, Obama fired back, pointing to McCain's own statement two years ago that he'd be willing to negotiate with the Palestinian militant group Hamas.
SEN. BARACK OBAMA: John McCain has repeated this notion that I'm prepared to negotiate with terrorists. I have never said that. I have been adamant about not negotiating with Hamas, a terrorist organization that has vowed to destroy Israel and won't recognize them.
In fact, the irony is, yesterday, just as McCain was making these attacks, a story broke that he was actually guilty of the exact same thing that he's accusing me of and, in fact, was saying that maybe we need to deal with Hamas.
I mean, that's the kind of hypocrisy that we've been seeing in our foreign policy, the kind of fear-peddling, fear-mongering that has prevented us from actually making us safe.
They're trying to fool you; they're trying to scare you; and they're not telling the truth. And the reason is, is because they can't win a foreign policy debate on the merits.
But it's not going to work. It's not going to work this time, and it's not going to work this year.
JUDY WOODRUFF: John McCain responded during an address to the National Rifle Association convention late this afternoon in Louisville.
SEN. JOHN MCCAIN: Earlier today, Senator Obama made a few remarks I'd like to respond to. I welcome a debate about protecting America; no issue is more important.
Senator Obama claimed all I had to offer was the, quote, "naive and irresponsible" belief that tough talk would cause Iran to give up its nuclear program. He should have known better.
I have some news for Senator Obama: talking, not even with soaring rhetoric, unconditional -- in unconditional meetings with a man who calls Israel a stinking corpse and arms terrorists who kill Americans will not convince Iran to give up its nuclear program.
It is reckless. It is reckless to suggest that unconditional meetings will advance our interests.
You know, it would be a wonderful thing if we lived in a world where we don't have enemies, but that's not the world we live in. And until Senator Obama understands that reality, the American people have every reason to doubt whether he has the strength, judgment and determination to keep us safe.
JUDY WOODRUFF: McCain went on to call Iran the "biggest state supporter of terrorists, with a declared desire to destroy the state of Israel."