Matt Steinglass compares America's relationship with Egypt to its relationship with Iran:
Our position today is in some ways less like our position during the Green Revolution in Iran than it is like Mikhail Gorbachev's position during the Velvet Revolution in Czechoslovakia, or perhaps like John F. Kennedy's position in South Vietnam in 1963, when a signal that America would be receptive to a change of leadership quickly led to the coup that ousted Ngo Dinh Diem.
That's not to say that Mr Obama should openly demand that Mr Mubarak step down.
That coup in South Vietnam didn't work out so well, and from the perspective of most Russians today, Mr Gorbachev's actions in Eastern Europe in 1989 were disastrous for Russian interests. Mohammed ElBaradei may proclaim that a post-Mubarak Egypt will be democratic and secular, but Mohammed ElBaradei is a retired United Nations official; there is no organised movement pledging fealty to him. He looks very much like a Kerensky figure, the sort of well-known educated liberal internationalist who appears initially popular at the beginning of a revolution and is appealing to foreigners, but who is soon swept aside once the battle for power descends to the streets.
(Photo: Egyptian demonstrators gather at dusk in Tahrir Square in Cairo on January 31, 2011, on the seventh day of protests against long term President Hosni Mubarak. By Mohammed Abed/AFP/Getty Images)