Amid Tunisia’s political upheaval, it is easy to hear echoes of the events in Egypt eight years ago. In 2013, widespread protests against an unpopular Islamist government allowed General Abdel-Fattah El-Sisi to take power in what amounted to a coup.

Tunisia’s President Kais Saied may not wear military fatigues, but he’s doing a pretty good Sisi impression nonetheless. Taking advantage of demonstrations against an unpopular Islamist-backed government, he has suspended the country’s elected parliament and sacked the prime minister, effectively assuming dictatorial authority over the country...