Yemen president's ouster could deal U.S. huge setbacks, By Jeffrey Fleishman, Los Angeles Times, March 22, 2011, 4:29 p.m.

Yemen strategically borders the Red Sea, the Gulf of Aden and Saudi Arabia. If Saleh is overthrown civil wars could erupt in both north and south, the Saudis would be rattled and possibly intervene militarily, Iran would almost surely exploit the chaos and the U.S. would be dealt a major setback in containing Al Qaeda in the Arabian Peninsula, an entrenched terrorist affiliate.

The drought-prone, poverty-stricken country, with oil tankers skimming its coast and pirates plying its waters, has over the years been largely neglected by the outside world. But with Saleh's government on the verge of collapse, Washington is focusing on the multiplying dangers that could turn the country into an ungovernable haven for militants and a proxy for struggles between regional powers.
The U.S. and other Western powers are not particularly fond of Saleh, who has ruled with a with an authoritarian swagger for 32 years and allowed for no potential successors outside his corrupt inner circle. But like the recently toppled presidents of Egypt and Tunisia, he has been an ally, although at times a reluctant one, in battling Islamic militants and keeping a semblance of order at the turbulent intersection of the Middle East and the Horn of Africa.
There is also concern over the religious passions of whoever succeeds Saleh. A leading candidate is Maj. Gen. Ali Mohsin Saleh Ahmar, the country's most powerful military commander, who defected to the protesters Monday. He is sympathetic to radical political Islam and may embolden the country's fundamentalist clerics.
Islamic militants are only part of Yemen's problems. The secessionist movement in the south, driven by communists, socialists and opportunistic tribesmen, threatens to split the country in half. Since Yemen was stitched back together after the 1994 civil war, the south has sought to break from Saleh. Rebel fighters have their own flag emblazoned on their rifle stocks.
The atmosphere remains precarious in the north, where years of intermittent fighting between government troops and Houthi rebels have left hundreds dead, destroyed villages and forced more than 300,000 people from their homes. The rebels, who belong to a Shiite Muslim offshoot, have long complained of economic discrimination. The struggle is not over religion, but Sunni Muslim-run Saudi Arabia has accused Shiite-controlled Iran of aiding the insurrection.