By Bill O'Reilly

Well, the campaign is heating up. The Iranian tyrant Ahmadinejad in New York today, again threatening Jews and demeaning gay people. That's what the man does.

But Ahmadinejad is also presiding over the building of a nuclear weapon. Thus, the irrationality and aggressiveness of Iran is a primary presidential issue. Today at the United Nations, President Obama said this.

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PRESIDENT OBAMA: America wants to resolve this issue through diplomacy and we believe that there is still time and space to do so. But that time is not unlimited. A nuclear armed Iran is not a challenge that can be contained. The United States will do what we must to prevent Iran from obtaining a nuclear weapon.

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O'REILLY: Now the word "must" is the key here because nobody really knows what that means. Even Mr. Obama might not know. But it sounds tough. However, Mitt Romney isn't buying it.

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MITT ROMNEY: The President has not drawn us further away from a nuclear Iran. In fact, Iran is closer to having a weapon, closer to having nuclear capability than when he took office. This is the greatest failure that might fit (ph) in to his foreign policy.

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O'REILLY: In a time when the economy is dominating the campaign in the USA, it is worth noting that we Americans remain in danger from Muslim fanatics like Ahmadinejad. And that danger "must", note the word, be dealt with.

According to a new Rasmussen poll, 45 percent of likely American voters believe that U.S./Muslim relations are worse now than they were four years ago. Just 18 percent say relations are better. That would seem to indicate a failure in the Obama foreign policy. Yet the President will point to the decimation of al Qaeda and the killing of bin Laden to persuade voters that he is not soft on the Muslim jihad.

So, this issue is a bit confusing and to be fair to President Obama opinions about his Muslim outreach are inconclusive at this point. Most Americans don't want war with Iran because that would send oil prices through the roof, hurt us all and possibly lead to World War 3.

However, there is no way on this earth that Israel is going to allow Iran to develop a nuclear weapon. The Israelis will attack the Iranians. They will attack. It's just a matter of when.

So Americans must decide which presidential candidate can better manage the situation. Things have not changed in Iran since Mr. Obama took office, except the Iranians are further down the road to the development of the nuclear weapons.

Governor Romney says he would get tougher with the Iranians by supporting Israel to a greater extent. It's an incredibly difficult situation but one that all Americans should be thinking about.

And that's "The Memo."

— You can catch Bill O'Reilly's "Talking Points Memo" weeknights at 8 and 11 p.m. ET on the Fox News Channel and any time on foxnews.com/oreilly. Send your comments to: oreilly@foxnews.com.