On February 5, 2003, then Secretary of State Colin Powell promised the world that the United States had proof Saddam Hussein was amassing and concealing weapons of mass destruction. Virtually everything he said was wrong. How much damage did that do to the standing of the United States?
"I know Secretary Powell, and I have the highest regard for him. I worked for him. And he's a man of great integrity. And what he said was what we believed as a country, to be true. It turned out not to be true. But it wasn't knowingly misleading the world," said Khalilzad. "I suppose the lesson is that we need to be cautious about the level of certainty with which we speak."
It begs the question: the next time an American ambassador or official says there is a threat to world security, who's going to believe him or her?
"I think we would have to work extra hard to convince countries," said Khalilzad.
Now, Iran's nuclear programs are the focus of the Bush administration -- but this time, the approach, so far, is very different.
The Bush administration has worked slowly and patiently through the U.N. to impose sanctions on Iran. Nevertheless, the president insists "all options are on the table."
Khalilzad said that sanctions only work in "rare circumstances," but they are the first step necessary before taking tougher action. In time, he said, it will become clear whether Iran can be sanctioned out of its nuclear ambitions -- or whether "tougher measures" will be put on the table.
It's hard slogging, diplomacy at the U.N. But sometimes, something must be done.
Last month, after violence and intimidation marred the election in Zimbabwe, the U.N. condemned Zimbabwean President Robert Mugabe in strong terms -- a rare moment of agreement. But did it affect the people of Zimbabwe?
"Well, it has helped them to the extent that they know that they are not alone, that the world is with them, that the government that is oppressing them is isolated in the world," Khalilzad said.
The U.S. is now seeking sanctions against Mugabe. So far, the Security Council has not acted.
Time is running out for Khalilzad at the U.N. The president he serves is a lame duck, and the international community is in the throes of full-on Oba-mania. There's "no doubt," said Khalilzad, that Obama's nomination has had a positive effect on the world's image of America.
"There is excitement, there is curiosity. The fact that an African-American has become the nominee of one of the major parties -- could be the next president of the United States -- is, in the U.N. context, they don't quite believe it, and I think this has been good for our country."
In the end, then, the big problems, such as Iran, terrorism, and nuclear proliferation will await the next president, whoever that might be.
Khalilzad will be gone. But there's no question his tenure at the U.N. has changed the tone the U.S. takes here. And, after the turmoil of the last few years, that counts as progress.