AT KING NORODOM SIHANOUK'S 73RD birthday four weeks ago, his half-brother Prince Norodom Sirivudh drew hearty applause for a soulful rendition of Georgia on My Mind. He won't be entertaining again for a while. Accused of plotting to assassinate co-Prime Minister Hun Sen, the former Foreign Minister was detained last week, first in Phnom Penh's filthy T3 prison and then in a room at the Ministry of Interior. The Prince's alleged plot prompted Hun Sen to order tanks into the capital's streets, throwing the government into chaos and infuriating King Sihanouk, who had demanded that his brother not be jailed. Late last week, after threatening to leave the country in protest, Sihanouk decided to stay, although his plane was ready to go at a moment's notice.

For now, the King's decision has averted an escalation of Cambodia's latest political crisis. But it resolves nothing. Sirivudh, 44, has been charged with criminal conspiracy and "acts to destroy the Royal Government of Cambodia." If convicted, he could go to jail for life. But the main evidence against the Prince is a scratchy recording of a cellular-phone conversation involving a passport-manufacturing contract. During the exchange, one apparently high-ranking official tells another, "If this is not resolved, I will kill Hun Sen ... and I always do what I say." Sirivudh is renowned for saying just about anything to get his audience's attention, and some who have heard the tape even doubt that the voice is his. "I am not a criminal," said Sirivudh hours before being escorted to prison by a convoy of heavily armed troops.

While the Prince's future plays out in legal proceedings that may take as long as six months, Cambodia's recent political theatrics are beginning to distract its most important audience: investors and aid donors. In the past six months, co-Prime Ministers Hun Sen and Norodom Ranariddh have loudly threatened opposition politicians and jailed dissident newspaper editors. Before the recent crackdown, foreign businessmen were just beginning to feel confident about investing in Cambodia. "Now," concedes Bombay-based pharmaceutical trader Ashish Bhatia, "everyone I talk to is holding up again."

One question that haunts many analysts is why Sirivudh, who has invested so much in rebuilding the country, would stoop to plotting the assassination of its most powerful leader. A French-trained economist and member of the resistance against Vietnam's occupation of Cambodia in the 1980s, the Prince returned to Phnom Penh in 1991, the first member of the royal family to do so. He jumped into a melting pot of a government, along with communists who had stayed and exiles who were coming back from jobs as waiters in Baltimore and law professors in France. Those disparate backgrounds have always been a source of political tension in the new Cambodia. "Ever since we arrived here, we have heard nothing but talk about threats, conspiracies, murder and plots," Sirivudh's French wife Christine says. "I suppose that is difficult to explain to the outside world, but these are typical topics of casual conversation here."

In other words, Sirivudh may have said it, but he didn't mean it. So why was he taken seriously? A regular critic of government corruption and his own party's inertia, the Prince has made plenty of enemies. As secretary general of the royalist FUNCINPEC Party, he was viewed by many as a potential threat to Ranariddh. (Christine was furious last week that the co-Prime Minister, a family member after all, had not bothered to call the Prince since the arrest.) With Sirivudh sidelined, Ranariddh now has undisputed control over FUNCINPEC. That may be a mixed blessing. The royalist party lacks support, and was even forced to postpone a long-scheduled congress this month because of organizational problems. On the dusty, potholed 18-km road that runs from Siem Reap to Cambodia's largest lake, the Tonle Sap, for example, there are eight Cambodian People's Party offices. The single FUNCINPEC office looks shut.

Whether or not Sirivudh is cleared, analysts in Phnom Penh say Ranariddh will have to rely heavily on a new generation of politicians to make his party credible. Many in that new group may be more interested in the opposition than the mainstream. Last Friday afternoon the headquarters of former Finance Minister Sam Rainsy's new Khmer Nation Party was deluged by supporters seeking membership cards. In the short term, of course, the main beneficiary of Sirivudh's arrest is Hun Sen. He avoided the public after ordering the tanks out two weeks ago, but Saturday the former Khmer Rouge guerrilla tearfully warned a rally of rural supporters than he still feared for his life. By outflanking a compliant Ranariddh, Hun Sen may have shown who the real king of Cambodia is.

--With reporting by Matthew Lee/Phnom Penh