With Egypt's military leading a hoped-for drive to democracy, President Barack Obama's senior military adviser was heading to the Mideast Saturday after losing an allied regime in the region.
The US is to reassure two allies, Jordan, which is facing its own rumblings of civil unrest, and Israel, which sees its security at stake in a wider transformation of the Arab world.
Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, was stopping first in Amman for meetings Sunday with senior Jordanian officials, including King Abdullah II.
Jordan has seen five weeks of protests inspired by unrest in Tunisia and later Egypt, though the numbers of marchers has been decreasing.
Mullen was then traveling to Tel Aviv for meetings and ceremonies Sunday and Monday marking the retirement of his Israeli counterpart, Lt. Gen. Gabi Ashkenazi, and talks with Prime Minister Benjamin Netanyahu and President Shimon Peres. Mullen had no plans to visit Egypt on this trip.
Israel is deeply worried about the prospect that Hosni Mubarak's ouster could lead to the emergence of a government less friendly to the entity.
Israel and Egypt fought four bitter wars before a peace treaty was reached in 1979. Mubarak, who was ousted Friday after 30 years of rule, had maintained the peace deal after succeeding Anwar Sadat, who was assassinated by two years after signing it.
Netanyahu has warned that any new government in Cairo must maintain their peace deal; Israel's first with an Arab nation.
A great deal is at stake for the US in the outcome of Egypt's drive to create a democracy out of the autocratic system over which Mubarak presided for three decades, with Washington a key political and financial supporter.
Both Egypt and Jordan have played leading roles, along with the US, in seeking a peace settlement between Israel and the Palestinians. Egypt also controls the Suez Canal, a key route for global oil shipments.
The US has provided $1.5 billion a year to Egypt, largely in the form of military assistance, and the White House has said the possibility of changing that would depend on how the current crisis unfolds.
The reverberations from Cairo are already being felt in significant ways in other Arab countries that are key US allies.
Jordan's new prime minister, Marouf Bakhit, promised Wednesday to continue political reforms demanded by protesters who forced King Abdullah II to reshuffle the Cabinet February 1.
The changes in Amman followed protests by thousands of Jordanians who had demanded jobs, lower food costs and a change to an election law that they say gives government loyalists more seats in parliament.
US-Jordanian military ties are among the strongest in the Arab world. And the revelation that a Jordanian intelligence officer was among the victims of a December 2009 suicide bombing in Afghanistan that also killed seven CIA employees pointed to the close and extensive cooperation on "counterterrorism" between US and Jordanian intelligence agencies.
When he ascended to the throne in 1999, King Abdullah II vowed to press ahead with political reforms initiated by his late father, King Hussein.
The first parliamentary election were held in 1989 after a 22-year gap, the multiparty system was revived and the suspension of martial law, which had been in effect since the 1948 Arab-Israeli war.
But little has been done since then.
In Saudi Arabia, a traditional cornerstone of US interests in the Mideast, a group of opposition activists said Thursday they asked the nation's king for the right to form a political party in a rare challenge to the absolute power of the ruling dynasty.
"You know well that big political developments and attention to freedom and human rights is currently happening in the Islamic world," the activists said in a letter to King Abdullah, who was one of Mubarak's staunchest supporters up until the end.
Last week, Yemen's President Ali Abdullah Saleh, yet another key US ally in office for more than three decades, mildly responded to pressure from protesters and announced he would not seek re-election in 2013 and would not try to pass power to his son.
Yemen, home to a branch of Al-Qaeda, is an important battleground for US campaigns in the region.