Updated

The U.S.-led plan to remove Iraqi leader Saddam Hussein from power by force appears to have become a question of "when" rather than "if," but the "who" -- as in "who will take over when Saddam is gone?" -- still remains unanswered.

In a sign that American commitment is firming up, the State Department and the Pentagon -- for several years at odds over Iraq policy -- have teamed up to invite several Iraqi opposition groups to Washington this week for a meeting all sides agree will be very significant.

"This is a clear order from the top leadership and the president to march forward toward overthrowing Saddam," said Entifadh Qanbar of the Iraqi National Congress.

The INC, headed by Ahmad Chalabi, is the best-known opposition faction, serving as an umbrella organization for many smaller parties.

Chalabi will be joined at the meeting by leaders of other important groups, including the Constitutional Monarchy Movement, the Iraqi National Accord, two Kurdish parties and the Supreme Islamic Resistance of Iraq, which is based in Iran.

The loosely-bound Iraqi opposition movement has often been portrayed as a collection of disparate groups arguing over which faction's leader should take charge -- a criticism some analysts say applies to the United States' Iraq policy as well.

"Their divisions were a total reflection of our divisions inside our government and our lack of seriousness," says Danielle Pletka, an Iraq analyst. "If they come together, it will be a reflection of their capabilities and our seriousness and commitment to the removal of Saddam Hussein."

Support from the Kurdish parties, for instance, is a crucial factor in any plans for Iraqi regime change.

The two Kurdish factions divide administration of an prosperous, semi-autonomous Kurdish state in the northern Iraqi "no-fly" zone, which was instituted by the U.S. and Britain at the end of the Gulf War as the Kurds rebelled against Baghdad's authority.

Previous Kurdish uprisings had resulted in horrific massacres at the hands of Saddam's troops, including the killings of thousands of civilians by poison gas in the late 1980s. At that time, the United States declined to intervene.

Not surprisingly, Kurdish leaders are less enthusiastic about a potential U.S. invasion than are the opposition figures operating out of London and Washington.

"We live there -- people's lives and livelihoods are on the line," said Barham Salah of the Patriotic Union of Kurdistan. "We cannot afford mistakes in this situation."

Pletka, however, said that an invasion looks more likely than ever.

"The decision to have meetings jointly is a sign that the administration is coming together under the president, as is appropriate," she says. "We are getting ready to move forward with the opposition."

"I hope it will happen as soon as possible," says the INC's Qanbar. "I've been ready for this for twenty years."