Introducing the surprising co-author of Obama's policy of engagement...

Meet Mahmoud Ahmadinejad, the face of engagement. Even during the presidential campaign, when talk of engagement arose, Iran was the poster child. If we could only hold our noses long enough to talk with them, America would gain an advantage. Engagement would elevate enmity into something more constructive, even if that was only debate.

But of course, engagement has a downside, the power to drag us down as well as lift our relationships up. No one seems so eager to demonstrate this or test the tolerances of this new policy than Ahmadinejad. Whether it is crushing democracy in his country, actively seeking nuclear weapons, threatening to wipe Israel off the face of the earth, seeking to extend his influence to the Western Hemisphere through his alliance with Hugo Chavez, continuing to sponsor Hezbollah or, as he did again today, calling the Holocaust a lie, he has done everything possible not only to raise tension with the United States but to serve as an affront to the most basic values and interests of the international community at large.

As a consequence of his actions, Ahmadinejad actually has claimed a new title for himself: co-author of America's policy of engagement. Once, many years ago, thoughtful security analyst Ed Luttwak said to me, "the dirtiest fighter sets the rules of a conflict." The same holds true for a policy like engagement ... especially during its early, developmental days. Obama may be the driving force behind it, but the individual or country with whom we continue to engage who offers the most extreme threats to our interests or our values will be the one who defines the limits of the policy.

If we can engage with a man like Ahmadinejad and make progress, then the power of a very tolerant form of engagement will be proven. If we let him prove that engagement is blind to all behaviors and over time that it has no influence over those behaviors, then he will undercut the theory ... or at the very least not only define the extent of what is acceptable to us but also define the limits of where engagement ought to be applied or be effective.

It was inevitable that someone play this role. In retrospect, it was also probably inevitable that it would be the Iranian president.

What was not so predictable was the courage of the Iranian people who once again, at great personal risk, gathered again in the streets today to shout "death to the tyrant" and to call for the end to Ahmadinejad's stolen presidency. It adds a complication as it poses the question: Does engaging with the regime undercut the movement to oust it or would we help them more by actively seeking ways to isolate Ahmadinejad and deny him the legitimacy of a place in the international community.

While the Russias and Venezuelas of this world might support him, we might well be able to put together a pretty strong coalition of actors who would not. Clearly, by any reasonable standards, a man like Ahmadinejad has no place at a UN General Assembly meeting. Through his undermining of democracy or his support of terror he is probably a criminal in terms of the letter of the law of most legal systems. Through his pursuit of his country's nuclear weapons program, his denials of his true intention and his history of lying he is flaunting international law. Through his denial of the Holocaust, he offends the very spirit that led to the creation of the United Nations in the first place. Finally, if there are no penalties, there are no disincentives to bad behavior.

The point is that for engagement to be effective -- and I still believe it can be -- we must reclaim the initiative to ensure that in the long run it is us, and not guys like Ahmadinejad, who must be the ones defining its limits and the consequences for exceeding them. (In a hint that they understand this point, UN Ambassador Susan Rice indicated that Obama did not expect to meet with Ahmadinejad in New York next week.)

We owe it to ourselves and also to those who share our interests ... at least some of them ... like the courageous people in the streets of Tehran.

ATTA KENARE/AFP/Getty Images