Egypt’s rocky transition to democracy has been further complicated by a judicial ruling today that dissolved parliament and sets the stage for renewed public protests and intensifying political struggle. A presidential runoff election is scheduled to begin Saturday, but the next president is likely to inherit a country with few effective institutions outside of the military, which is reluctant to relinquish its power and privileges.

Egypt’s army, which reluctantly ousted President Hosni Mubarak in a palace coup in February 2011, now appears to be launching a slow-motion pre-emptive strike against the political forces that pushed for Mubarak’s ouster. Egypt’s Supreme Constitutional Court, packed with holdovers from the Mubarak regime, today ruled that Egypt’s recent parliamentary elections were invalid because they had been conducted in an unconstitutional fashion. This means that Egypt’s parliament, dominated by the Muslim Brotherhood and other Islamists, will be dissolved shortly before Egypt’s presidential runoff elections, slated for Saturday and Sunday.

This gives the Supreme Council of the Armed Forces (SCAF), the military junta that has ruled Egypt since Mubarak’s downfall, a pretext to retain power despite its previous promises to transfer power to the winner of the presidential elections by the end of June. The SCAF reportedly will assume the legislative powers of the parliament and appoint a new constituent assembly to write a new constitution.

The bombshell judicial ruling may precipitate a popular backlash that could disrupt the presidential runoff election that begins on Saturday. In a separate ruling, the court also invalidated a law passed by the parliament that would have disqualified Ahmed Shafik, Mubarak’s last prime minister. Shafik, a former Air Force general who is closely aligned with the SCAF, welcomed the ruling and said, “The message of this historic verdict is that the era of political score settling has ended.”

But a new round of score settling is likely just beginning. A senior leader of the Muslim Brotherhood, which stands to lose the most from the ruling, warned that “If parliament is dissolved, the country will enter a dark tunnel—the coming president will face neither a parliament nor a constitution.”

The SCAF appears to be gambling that the Muslim Brotherhood will accept the ruling to enable its presidential candidate, Mohamed Morsi, to win the election this weekend. If the Brotherhood mobilizes its followers to protest the ruling, then the SCAF may exploit the resulting chaos to postpone or cancel the election, giving itself another rationale for holding on to power. The SCAF clearly is preparing for a possible backlash, and it authorized the armed forces yesterday to arrest civilians in the event of public protests.

Egypt has been plunged deeper into uncertainty and political instability. It is unclear if the SCAF will be able to sustain its judicial coup, if it is confronted with widespread public protests tomorrow. It often has overplayed its hand in the last 16 months and been forced to back down.

But the growing tensions and triangular power struggle between the SCAF, the Muslim Brotherhood-led Islamist camp, and the fading democratic youth activists are unlikely to be peacefully resolved in the long run.Egypt’s stagnated “Arab Spring” is likely to give way to a long hot summer of political struggle.