President-elect Barack Obama’s aides say he is considering making a major foreign policy speech from an Islamic capital during his first 100 days in office.

So where should he do it? The list of Islamic world capitals is long, and includes the obvious —Riyadh, Kuwait City, Islamabad — and the not-so-obvious — Male (the Maldives), Ouagadougou (Burkina Faso), Tashkent (Uzbekistan). Some wise-guys have even suggested Dearborn, Mich., as a possibility.

Clearly it would be cheating for Mr. Obama to fly to Detroit, talk to Dearborn’s 30,000 Arab residents and call it a day. And Male and Ouagadougou, while certainly majority Muslim, can’t really be what Mr. Obama’s aides have in mind when they talk about locales for a high-profile speech that would seek to mend rifts between the United States and the broader Muslim world.

So Burkina Faso and the Maldives are out. But that leaves a whole swath of Islamic capitals, all ready to be spruced up for Mr. Obama to make his speech. I’ve thought hard about this, and asked a few people — diplomats even — which capital Mr. Obama should pick.

The consensus, after an entire day of reporting, is Cairo.

Why Cairo? It’s a matter of elimination. I called Ziad Asali, the president of the American Task Force on Palestine, to gauge his thoughts. “Damascus would be cool, except it would look as if he was rewarding the Syrians and it’s too soon for that,” Mr. Asali said.

True. Maybe in a year, if Syrian President Bashar al-Assad gets around to a land-for-peace deal with Israel. But for right now, I’m not really seeing Damascus as the spot for the big speech.

What about Ramallah, I asked Mr. Asali, thinking it would show solidarity with the Palestinians.

“I would object to that on so many levels,” he shot back, irate. “Are you forgetting that Palestinians seek Jerusalem as their capital?”

Right. And giving the speech in Jerusalem would just open up a Pandora’s box full of problems. So that’s not happening.

My colleague, David Sanger, heard me talking about it and came over to my desk. “I think he’s going to pick Jakarta,” he said. “It would be a big homecoming-type trip.”

But Jakarta’s too easy. Mr. Asali thought so too: “Jakarta? People would yawn about that.” Sure, Indonesia is the world’s most populous Muslim-majority country — some 177 million Muslims live there — but the very fact that Mr. Obama once lived and went to school there would make choosing it seem like cheating.

Baghdad? Definitely out-of-the-box, but it could appear to validate the Iraq war, which Mr. Obama opposed. Beirut? Too many Hezbollah members — Secret Service would flip its collective lid — and anyway, the Lebanese president has always been a Christian.

Tehran? Too soon for that. Amman? Been there, done that. Islamabad? Too dangerous. Ankara? Too safe. Plus the Turks aren’t going to be too crazy about being used for outreach to the Muslim world when they’re trying to join the European Union.

I asked a senior Turkish diplomat what he thought. He immediately started acting, well, diplomatic. “We don’t have a problem with our Islamic identity,” he said. “But our system is secular.”

Riyadh? Mr. Obama’s national security aides say no.

Kuwait City? Abu Dhabi? Doha? “I don’t think it will be in the Gulf,” one foreign policy adviser to Mr. Obama said.

See? It’s got to be Cairo. Egypt is perfect. It’s certainly Muslim enough, populous enough and relevant enough. It’s an American ally, but there are enough tensions in the relationship that the choice will feel bold. The country has plenty of democracy problems, so Mr. Obama can speak directly to the need for a better democratic model there. It has got the Muslim Brotherhood, the Islamist organization that has been embraced by a wide spectrum of the Islamic world, including the disenfranchised and the disaffected.

The Secret Service won’t like it one bit, but Cairo is no Islamabad. I called the Egyptian Embassy in Washington to ask officials there what they thought. Someone from Mr. Obama’s team had already mentioned the possibility, although embassy officials said Egypt has not been approached about a possible presidential trip to Cairo.

Still, Sameh Shoukry, the Egyptian ambassador, e-mailed me a statement. “Needless to say, the President of the United States is always welcome in Egypt,” it said. “Delivering such a speech from Cairo would no doubt reinforce the intended message. Cairo has long been a center of Islamic learning and scholarship, in line with Egypt’s central role in the Middle East.”