Pushing ever harder, Barack Obama rejected as too little and too vague the uncertain assurances in a long, rambling speech by Egyptian strongman Hosni Mubarak.
Missing was a resignation.
"It is not yet clear that this transition is immediate, meaningful or sufficient," the U.S. President said in a blunt statement issued hours after Mr. Mubarak's televised speech enraged thousands of pro-democracy demonstrators who had spent the day in anticipatory celebration expecting an unambiguous resignation from the 82-year-old dictator.
After pushing for his ouster for weeks, Mr. Obama seemed poised to watch Mr. Mubarak take the fall and then was taken aback when it didn't happen.
He left no room for doubt that the United States had shifted its allegiance away from the ruling regime in Cairo that had been Washington's closest Arab ally for decades, to the multitude in the streets demanding Mr. Mubarak's immediate ouster.
The "Egyptian people will persevere, and they must know that they will continue to have a friend in the United States of America," Mr. Obama said, demanding that Mr. Mubarak "spell out in clear and unambiguous language the step-by-step process that will lead to democracy."
He also warned Egypt's powerful military against shooting the swelling throngs.
"It is imperative that the government not respond to the aspirations of their people with repression or brutality," said Mr. Obama in what amounted to a warning shot at Egypt's pampered officer class that is propped up by more than $1.3-billion in annual U.S. military largesse.
Mr. Obama's tough talk came after a day of frenzied expectation, heightened by the U.S. President himself.
"What is absolutely clear is that we are witnessing history unfold," Mr. Obama expectantly told an afternoon crowd in frigid Michigan shortly before the Egyptian dictator was to address his people.
Then, in the warm confines of the big blue-and-white Boeing 747 known as Air Force One, Mr. Obama watched Mr. Mubarak deliver a late-night speech in Cairo that skirted the single most pressing demand of the growing multitude of Egyptians: that he quit.
It was not what the already celebrating crowds in Cairo had expected nor what America's most senior intelligence official had publicly predicted.
Leon Panetta, the Central Intelligence Agency chief, had confidently told Congress in the morning: "There's a strong likelihood that Mubarak may step down this evening," something the Obama administration has been pressing for with increasing urgency.
After Mr. Mubarak failed to quit, the U.S. President huddled with his national security team to craft a response.
Meanwhile, Sameh Shoukry, Egypt's ambassador to Washington, claimed the Mubarak speech was - in fact - a full handover of all power to Omar Suleiman, 74, the newly named Vice-President, who formerly headed the feared and pervasive intelligence services. Mr. Mubarak, 82, would remain "de jure" president, the ambassador said.
"The Vice-President is the de facto president," Mr. Shoukry said.
It seemed too little too late, both for the throngs in the streets and the American President.
Last week, when Mr. Mubarak apparently ignored Mr. Obama's call to immediately begin an "orderly transition," the White House was openly impatient.
"Now means yesterday," Mr. Obama's spokesman, Robert Gibbs, said, explaining when the transition was supposed to get under way.