CAIRO — The Egyptian Parliament approved sweeping measures on Thursday that would allow President Abdel Fattah el-Sisi to extend his rule until 2034, further entrenching his authoritarian rule and enshrining in law the military’s dominance over the country.

The vote by Parliament, whose workings are quietly managed by Mr. el-Sisi’s intelligence agencies, sets in motion a fast-moving process of constitutional change that could culminate in a referendum within three months. The referendum’s approval is seen as a foregone conclusion.

The changes formally confirm what has become evident to many Egyptians for years: The sweeping euphoria of 2011, when protests led to the ouster of President Hosni Mubarak, has given way to an even harsher brand of strongman rule under a leader who also intends to rule for decades, and perhaps for life.

Washington’s unquestioning embrace of Mr. el-Sisi, whom President Trump has called a “great guy,” emboldened the Egyptian leader to act with little fear of American pushback.