Amr Abdallah Dalsh / REUTERS A general view shows protesters opposing Egyptian President Mohamed Morsi shouting slogans against him and members of the Muslim Brotherhood during a protest at Tahrir square in Cairo June 29, 2013.

In the upscale Cairo suburb of Heliopolis, about a 20-minute walk from the presidential palace, the rally was in full swing. “We swear to the blood of the martyrs,” the marchers chanted as they moved toward the palace. “A new revolution from the start!”

That, as much as anything, captured the mood of Sunday’s wave of national protests against President Mohamed Morsi and his Muslim Brotherhood organization. After a year under Morsi, preceded by a generally unhappy 15 months of postrevolutionary military rule, the protesters — angry about a weak economy, deteriorating security and rising Islamism — want a reset.

In terms of sheer numbers, Sunday’s anti-Morsi demonstrators had to be pleased with the turnout — in the hundreds of thousands. The figures equaled and possibly exceeded some of the highest peaks of the original revolution against deposed dictator Hosni Mubarak. Tahrir Square, on the edge of downtown Cairo, was packed to the point where crowds extended all the way across two bridges to the other bank of the Nile. And the crowds in Heliopolis were equally massive — completely covering the district.

(PHOTOS: Egyptians Protest the Rule of Morsi)

Yet, given the sheer undiluted rage directed at Morsi by many of his critics these days, Sunday’s protest atmosphere was surprisingly festive and optimistic. A large percentage of Sunday’s anti-Morsi demonstrators seemed to genuinely believe that their people-power movement will succeed in forcing Morsi from office — and relatively quickly. Rasha Soliman, a 40-year-old protester, offered this prediction regarding Morsi’s departure: “It will happen. Not in a day or two, but it won’t take a long time either.”

If this is indeed the beginning of a second Egyptian revolution, then it’s starting right where the first one ended. Back in February 2011, the protesters generally stuck to the Tahrir Square area for the majority of the 18-day uprising. It was only at the very end — when Mubarak provoked outrage by refusing to step down in a Feb. 10 speech — that protesters took their fight to the walls of the presidential palace. Within hours of that march reaching the palace, Mubarak was unceremoniously shoved from the stage by his own military and the next time anybody heard from him was months later addressing a judge from inside a courtroom cage.

This time, however, the fight is starting with direct confrontation with the presidency. Throughout the day, army helicopters hovered over the rally — with many of the demonstrators openly cheering them. While the military has remained cryptic about where it stands, a percentage of the anti-Morsi protesters openly welcome the intervention of the armed forces to end the stalemate.

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But amid the euphoria and talk of a second revolution, it’s worth noting that this is not 2011 and Morsi — no matter what his detractors say — is not Mubarak. He was democratically elected, with the votes of many of the same people calling for his ouster on Sunday, albeit by a thin margin. And Morsi has his own sincere and impassioned support base that sees the movement against him as a counterrevolutionary attempt to rob them of their own democratic rights.

On Sunday, the Brotherhood and its Islamist allies staged their own counterdemonstration at a mosque a short distance from the palace. The pro-Morsi demonstrations — numbered in the several thousands — passionately chanted in support of their embattled President and even unveiled a cake to celebrate the beginning of his second year in office. Egyptian TV channels resorted to showing as many as eight different screens to keep up with the competing rallies in the capital and those happening elsewhere in the country. Presidential spokesman Omar Amer was forced to hold two separate press conferences Sunday evening in order to react to events. Amer, in his comments, repeatedly and testily dismissed any talk of “concessions” from the President and instead offered yet another round of national reconciliation talks with an opposition that has largely sworn off talking to Morsi or his people. “The President has opened the door of dialogue to everyone,” said Amer. “Any request or input from any Egyptian citizen is welcomed.”

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Morsi, the Brotherhood and its affiliated Freedom and Justice Party have repeatedly claimed that he hasn’t been given a fair chance to rule and that one year is simply too short for this kind of backlash. But the sheer size, scope and diversity of Sunday’s anti-Morsi protests reveal, at the very least, a widespread dissatisfaction with his rule that the President will have to address in the coming days.

Morsi won’t have long to decide. Late Sunday night, organizers of the Tamarod (Rebel) campaign — the grassroots anti-Morsi signature drive that helped kick-start this latest wave of protests — announced it was giving Morsi a deadline of 5 p.m. Tuesday to announce his resignation and an early presidential election or it would launch a nationwide civil-disobedience campaign. Egypt remains on edge.

Khalil is a Cairo-based journalist and author of Liberation Square: Inside the Egyptian Revolution and the Rebirth of a Nation.