BEIRUT, Lebanon — Lebanon is used to affronts to its sovereignty. Israel occupied part of the country for years. Syrian troops stayed even longer. Then the Lebanese militant group Hezbollah fought a war with Israel, and waged another in Syria, as the Lebanese government watched. The United States, France and Britain have, over the past century, done their share of meddling.

But no one has seen anything quite like the spectacle that has played out over the past few days. Saad Hariri, the prime minister, who had previously shown no signs of planning to quit, unexpectedly flew to Saudi Arabia and announced his resignation from there, to the shock of his own close advisers. He has not been back since, and no one is sure when, or if, he is returning.

Hours after Mr. Hariri’s announcement — televised Saturday on a Saudi-controlled channel — Saudi Arabia’s assertive new crown prince, Mohammed bin Salman, presided over the roundup of some 500 people, including 11 princes, on corruption charges.

Lebanon broke out the popcorn.

In a country where political analysis is a near-universal hobby, and where political power is — to oversimplify a bit — divided between Mr. Hariri’s Sunni, Saudi-backed party and the Shiite, Iran-backed Hezbollah, speculation was immediate that Mr. Hariri was also being held against his will. He holds dual Lebanese and Saudi citizenship and has extensive business dealings in the Persian Gulf kingdom.