(CNN) -- It was 17 days of expanding unrest that finally prompted the Egyptian military Thursday to nudge President Hosni Mubarak from power, analysts said.
The recent trends of labor unions and professionals such as doctors joining the mass street protests signaled to the Egyptian military that Mubarak's hold on power seemed untenable and endangered the good standing of the armed forces itself in Egyptian society, analysts said.
"The military had to ask itself, 'Are we going to go down with Mubarak?' " said William Quandt, a professor of politics at the University of Virginia and a National Security Council staff member in the 1970s who was involved in the Egyptian-Israeli peace treaty. "The military said we are the backbone of the regimes, and we are pretty popular with the people."
The army also saw how demonstrators became re-energized after Wael Ghonim, a cyberactivist who is a Google executive on leave, was freed from official Egyptian captivity and gave an impassioned speech to protesters in Tahrir (Liberation) Square, Quandt said.
With yet another massive street protest predicted again Friday in Egypt after weekly worship services, the military that's been the backbone to Egypt's secular strongmen since 1952 seemed to have had enough, Quandt and other analysts said.
In its strongest maneuver yet, the military's senior officers Thursday issued "Communiqué No. 1," as if more were forthcoming, stating that their discussions were ongoing on "what can be achieved to preserve the homeland and the gains of the Egyptian people."
That communiqué set up an expectation among street protesters in Cairo that Mubarak would resign.
Instead, Mubarak announced that he would be turning over his day-to-day powers to his hand-picked vice president, Omar Suleiman, an action that makes Suleiman the de facto president of Egypt and head of the military, said Egyptian ambassador Sameh Shoukry to the United States.
Mubarak remains the de jure, or matter of law, president, Shoukry said, attributing the information to the Egyptian government.
"The hardliners in the regime were hoping that an attrition strategy would work, and people would leave the square, and in fact, yesterday was one of the biggest turnouts ever because of the release of this Google guy and the unions declared their solidarity and so did the doctors," Quandt said.
Then the state-run newspaper Al-Ahram broached the subject of the "revolution" and said the people's demands were legitimate, Quandt said Thursday.
The military was worried about becoming the heavy in carrying out Mubarak's draconian responses to the uprising, Quandt said.
The military felt "the sentiment is going to turn against us, and we don't want that to do that and we want to remain a people's army," Quandt said.
Another key moment occurred Thursday when Defense Minister Mohammed Hussein Tantawi led the military's supreme council without its commander, Mubarak, and vice president Suleiman, who is a hard-line loyalist to Mubarak and his former intelligence chief, analysts said.
The supreme council gathering was particularly significant for Tantawi, who had long been derided by mid-level military officers as being obsequious to the president, analysts said.
"The longer that this political crisis unfolded, it appears that there was fragmentation among the transitional government," said Joshua Stacher, assistant professor of political science at Kent State University in Ohio and an expert on Egypt who met last month with White House National Security Council officials about the Egyptian crisis.
"I think it came down to the question as to who had more generals on their side," Stacher said. "It looks like that was Tantawi, the minister of defense who has been described as 'Mubarak's poodle.' But as minister of defense, he would be in the chief position to dispense a lot of patronage to the military. So he would have had a lot of personal relationships with generals."
What leadership role in the ongoing changes will the military play next, analysts asked.
Thursday's moves by the military resembled the Free Officers Movement of 1952-54, when a group of officers, led by the future President Gamal Abdel Nasser, toppled the monarchy, according to analysts for the global intelligence company Stratfor of Austin, Texas.
But an internal power struggle between the grandfatherly figure of Gen. Muhammad Naguib, the country's first president, and then-Col. Nasser concluded with a Nasser takeover and ascension to power, analysts said.
Stacher wondered if Tantawi is becoming a figure akin to Nasser, he said.
"There's going to be a question of whether this is really a regime change or not," Stacher said. "There is a lot of this that seems like déjà vu between 1952 and 1954."
With high expectations early Thursday that Mubarak would outright quit, many street protesters in Cairo reacted in anger when Mubarak didn't completely abandon office Thursday, and hundreds of demonstrators marched to the presidential palace to denounce Mubarak.
"This now creates a massive crisis for the Egyptian military," Stratfor analysts said in a statement. "Its goal is not to save Mubarak but to save the regime founded by Gamal Abdel Nasser.
"The military faces three choices. The first is to stand back, allow the crowds to swell and likely march to the presidential palace and perhaps enter the grounds. The second choice is to move troops and armor into position to block more demonstrators from entering Tahrir Square and keep those in the square in place. The third is to stage a coup and overthrow Mubarak," the analysts said.
Egypt's ongoing crisis could cease if thousands of protesters reflect on how Mubarak gave up the presidency for all practical purposes and end their show of force Friday, analysts said.
But that seemed unlikely Thursday, as protesters even gathered around the state-run media offices in Cairo.
"Therefore the Egyptian military has some choices to make," the Stratfor analysts said.