BEIRUT, Lebanon — In Libya, armed militias have filled a void left by a revolution that felled a dictator. In Syria, a popular uprising has morphed into a civil war that has left more than 100,000 dead and provided a haven for Islamic extremists. In Tunisia, increasingly bitter political divisions have delayed the drafting of a new constitution.

And now in Egypt, often considered the trendsetter of the Arab world, the army and security forces, after having toppled the elected Islamist president, have killed hundreds of his supporters, declared a state of emergency and worsened a deep polarization.

It is clear that the region’s old status quo, dominated by imperious rulers who fixed elections, ruled by fiat and quashed dissent, has been fundamentally damaged, if not overthrown, in the three years since the outbreak of the uprisings optimistically known as the Arab Spring. That was amply illustrated on Wednesday in Egypt, where a reversion to the repressive tactics of the past was met with deep outrage by Islamist protesters who had tasted empowerment.

What is unclear, however, is the replacement model. Most of the uprisings have devolved into bitter struggles, as a mix of political powers battle over the rules of participation, the relationship between the military and the government, the role of religion in public life and what it means to be a citizen, not a subject.