But there are still fears that anti-government sentiment in the key U.S. counterterrorism ally could explode into unrest like that in other states like Egypt and Tunisia.
Administration officials told The Associated Press that Yemeni President Ali Abdullah Saleh's announcement that he would not seek another term in office or try to pass power to his son was "positive" and "significant." They allowed that it remained to be seen whether Saleh would fulfill the pledges.
The situation in Yemen is of particular worry because it is the home of al-Qaida in the Arabian Peninsula, the terror group that U.S. officials believe poses the most immediate terror threat to America.
And, with the threat of violence growing as a result of the unrest, U.S. counterterrorism officials are worried that Yemeni security forces will be more focused on protecting the government, allowing AQAP to take advantage of any diminished scrutiny.
The officials spoke on condition of anonymity because they were not authorized to speak publicly on the matter.
"There is a lot to be concerned about. This is a country awash in guns, things can get violent a whole lot faster," said Christopher Boucek, a Yemen expert at the Washington-based Carnegie Endowment for International Peace.
"The most active branch of al-Qaida is in Yemen and we know they're dangerous," he added. "The failure or the fall of the Yemeni government would be very bad for America. There is not a group in Egypt that's tried to blow up American airliners."
Rep. Adam Smith, the top Democrat on the House Armed Services Committee, said the U.S. needs a government in Yemen that can be a strong partner to continue the counterterror fight there.
"This is a very volatile and unpredictable situation, and the risks are significant," Smith said. "If the government in Yemen becomes weaker, then it's easier for al-Qaida to find a safe haven to operate in."
The key, he said, is who replaces the Saleh regime, if it collapses. If it's a stronger government, it could be a positive thing for the U.S., he said, but if it's one sympathetic to AQAP's views, then that will be a bigger problem.
The U.S. has stepped up its own campaign against al-Qaida militants in Yemen, including the use of missile strikes made public in the recent release of State Department cables by the WikiLeaks website.
At the same time, the U.S. has provided special operations forces to help train and equip Yemeni troops.
A key U.S. concern is that there will be less cooperation from the Yemeni government, which could find it difficult to do the terror screening or other monitoring of possible threats.
AQAP, Boucek said, benefits from any chaos that engulfs the Yemeni government.
The government is "trying to negotiate their political future. They're not focused on AQAP. The more security forces they bring to the capitol, the more that are not going out after AQAP," he said.
The U.S.-born radical cleric Anwar al-Awlaki, thought to be hiding in Yemen, is believed to have inspired and even plotted or helped coordinate some of the recent attacks on the U.S. That includes the failed Christmas Day 2009 bombing of a Detroit-bound airliner and the also unsuccessful plot to send mail bombs on planes from Yemen to the U.S. in October.
Al-Awlaki also is believed to have inspired the deadly 2009 shooting rampage at Fort Hood, Texas, and had ties to some of the 9/11 hijackers.