President Barack Obama no longer backs Hosni Mubarak's regime in Egypt, according to a White House statement released on Sunday.

In calls to a number of foreign leaders - including Prime Minister Erdogan of Turkey, Prime Minister Netanyahu of Israel, and King Abdullah of Saudi Arabia - President Obama said he supports an orderly transition to a government that is responsive to the aspirations of the Egyptian people.

The Mubarak regime was previously considered a U.S. ally and the support from the U.S. government was one factor that deterred challenges from opposition groups.

Now, this recent reversal of position is a huge blow to the Egyptian ruler.  (Indeed, in an interview aired by PBS just last Thursday, Vice President Joe Biden said Mubarak was no dictator and should not step down.)

Now, as Obama withdraws his support, protesters and opposition groups are emboldened.  Furthermore, for key parties that haven't clearly picked a side yet - mostly importantly the military - Mubarak's camp just became less attractive.