As Thailand's ailing 81-year-old King Bhumibol Adulyadej begins the second month of a hospital stay Monday, his countrymen are wondering just how sick he really is.

Concern for his well-being reflects the reverence and affection the Thai public holds for the king, who ascended to the throne in 1946 and is the world's longest-serving head of state. But of equal yet generally unspoken concern to Thais—most of whom have known no other monarch—is the question of what lies ahead in the post-Bhumibol era, whenever it comes.

Thailand is still reeling from more than three years of almost constant and sometimes violent political turmoil and there is worry about what effect the loss of the king would have.