As Egyptians filled the streets of Cairo Friday to celebrate the resignation of President Hosni Mubarak, political leaders and commentators demonstrated excitement for the people of Egypt and urged a peaceful and democratic transition.

As news of Mubarak’s resignation spread, voices echoed across the web offering exuberant praise for Egypt’s protestors, largely credited with bringing about the leadership transition.

On Twitter, congratulatory words lauded the youth who started the revolution; “Congrats Egypt” quickly became a trending topic. 

House Minority Leader Nancy Pelosi (D-CA) tweeted that the Egyptians were “an inspiration to the world.”

New York Times columnist Nicholas Kristof wrote, “So, all of you Tunisians and Egyptians, ‘mabrouk’ or ‘congratulation’”! You’ve made history. The score in Egypt is: People Power, 1; Police State, 0.”

In a televised speech, President Obama pronounced, “The people of Egypt have spoken, their voices have been heard, and Egypt will never be the same.”

Along with words of encouragement and excitement for the Egyptian protesters, other commentators focused on the challenges in the upcoming transition.  Several cautioned that rule by the military may only help maintain the anti-democratic status quo that Mubarak’s administration had fostered.

Kristof declared, “I worry that senior generals may want to keep (with some changes) a Mubarak-style government without Mubarak.”

Max Fisher of the Atlantic posted a reminder that establishing democracy in Egypt is a long process, of which Mubarak’s resignation is only the beginning: “Whatever path Egypt follows, it's important to remember that governments do not transform overnight. Mubarak may be on his way out, but regimes are not confined to one man.”

Several lawmakers and commentators emphasized that the U.S. should offer support for Egypt to promote a peaceful transition, such asRep. Keith Ellison (D-MN), who stated, “While the resignation of President Mubarak is a monumental step, it is a first step. Egypt's transition to true democracy will require continued support from the United States and peace loving nations throughout the world."

Some authors warned of even darker threats to establishing democracy. 

In a piece in the Washington Post, Jon Alterman, Middle East program director at the Center for Strategic and International Studies, a Washington-based think tank, goes even further warning of the potential danger of military rule of Egypt: “…the army's return suggest a huge step backward. Military rule does not allow for bargaining between interest groups, nor does it presage a constitutional convention between an array of actors in Egyptian political life. Rather, it suggests even heavier management of the political process, on the one hand, and the removal of any timeline for change on the other.”

In a post on the blog Red State, Joshua Trevino argues that a prolonged transition period could pose dangers to the establishment of democracy:  “Here is the hard truth about Egypt now: if the revolution was merely to depose Hosni Mubarak, it has won. But if it was to seize liberty, it is not over. Signs of a long and protracted “transition” period are already emerging…” 

In a statement, House Foreign Affairs Committee chairwoman Ileana Ros-Lehtinen (R-FL) warned that the crisis in Egypt could give rise to more extremist factions such as the Muslim Brotherhood: “We must urge the unequivocal rejection of any involvement by the Muslim Brotherhood and other extremists who may seek to exploit and hijack these events to gain power, oppress the Egyptian people, and do great harm to Egypt's relationship with the United States, Israel, and other free nations.”