“We are a river country,” an Egyptian friend once told me when I marveled at his country’s patience with corrupt, incompetent and repressive regimes. “We go on and on.”

Perhaps. But that legendary patience with the bumbling but stubborn, 82-year-old President Mubarak seems to be wearing out.  Change is coming to Egypt, either very soon or shortly thereafter. And what happens in Egypt matters, to Egyptians, of course, but also to the U.S., Israel and the entire Arab world.

Diminished as it may be today, Egypt remains the centerpiece of the Arab world. With its population of 80 million, it is not only the largest Arab country. It is historically, culturally and intellectually the heart of the Arab crescent from Morocco to Lebanon. An old saying in the region is that there can be no peace between Israel and her Arab neighbors without Syria, and no war without Egypt. It is still true today. No surprise that President Obama chose Cairo for his first major speech on relations between the U.S. and the Arab and Muslim world.

But now Obama confronts the ticklish task of encouraging change in Egypt without seeming to abandon the Mubarak government .  Egypt has served as a crucial counterweight to Syria and Iran. It has received tens of billions of dollars worth of U.S. aid over the years and carved out a cold but diplomatically important peace with Israel. As Egypt goes, so go Jordan and Saudi Arabia. The stakes are enormous.