The military ouster of Egyptian President Mohammed Morsi will likely have ramifications far beyond the ancient country's borders, potentially affecting the balance of power in the Middle East, the influence the U.S. can wield in the region and the worldwide price of oil.
"Egypt sits at the center of the Mideast," said Joel Rubin, a former State Department desk officer for the region. "Cairo is the leading city in the Arab world ... and Egypt's government has always had a dominant role over the politics of the region."
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Egypt is "in many ways the most important country in the Middle East," said Isobel Coleman, a senior fellow at the Council on Foreign Relations, with the "biggest population, the largest economy and a geographically critical location. ... If it turns into a terrible, bloody civil war, it's just bad for the whole region. It destabilizes the entire region."
Here's a look at how Rubin, Coleman and other experts see things playing out:
What happens next
Adly Mansour, 68, chairman of the Supreme Constitutional Court, takes over as acting president during an unspecified transitional period. The military suspended the Islamist-backed constitution and said it hoped for early elections; before the ouster, Egyptian military officials reassured Washington that they had no stomach for ruling the country themselves, U.S. officials told NBC News.
In the next 24 to 48 hours, the U.S.'s crucial task is to "maintain an open channel with the head of the Supreme Forces of Egypt," said Marc Ginsberg, a former U.S. ambassador to Morocco and senior White House adviser for Middle East policy.
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"The State Department is probably going to dispatch [Defense] Secretary [Chuck] Hagel or Secretary [of State John] Kerry to the region or both to take a temperature of how willing the military is to turn over power," he told MSNBC.
While the U.S. State Department is removing non-emergency embassy personnel and approved family members from the country, the U.S. ambassador, Anne Patterson, will stay, at least for now.
About 550 U.S. Marines are on standby at Naval Air Station Sigonella on the Italian island of Sicily and at Morón Air Base in southern Spain. Defense officials told NBC News on Wednesday evening that no decision has yet been made on whether to send them to Cairo.