Malaysia’s unwieldy Pakatan Rakyat opposition coalition, born in 2008 and led by Anwar Ibrahim, is facing the biggest crisis of its existence and could come apart, costing it the leadership of Selangor, the country’s richest state, and potentially costing Malaysia its only alternative to the scandal-ridden Barisan Nasional led by the United Malays National Organization, whose popularity with voters continues to flag.

The issue is an internecine squabble over who should be the chief minister of Selangor. It could force a snap state election that might hand victory to the Barisan Nasional, the ruling national coalition, according to the head of a Kuala Lumpur-based think tank.

Others are less pessimistic. A Malay businessman said he thought the parties eventually would sort out the issue, and that UMNO is more concerned about a Selangor snap election than the Pakatan coalition because it also fears losing.

Anwar, in an interview with the popular website Malaysian Insider, expressed optimism that the leadership of the three-party coalition would look at larger interests. "We have already endured so long with principles like tolerance," he said. "I do not see it as a breakup."

The coalition certainly survived a string of crises to prosper in the 2013 general election despite the disparate nature of the three parties that make it up. But, say several sources in Kuala Lumpur, Anwar is preoccupied over concern that he might be jailed as the result of a guilty verdict rushed through an appellate court in March, reversing a 2012 high court verdict. That case, popularly known as Sodomy II, accused Anwar of having forced sex with a male aide. Anwar spent six years in a Malaysian prison from 1998 to 2004 on similar charges that were widely considered to be trumped up by former Prime Minister Mahathir Mohamad and UMNO officials to keep him from heading the opposition.

Critics say the appellate decision, in Malaysia’s malleable court system, was designed to stop Anwar from running in a by-election that could give him the right to become chief minister of Selangor -- a useful platform to take on the prime minister. Friends say Anwar is depressed and believes that he may well be back in prison before the end of the year. That, they say, has affected his ability to keep his fractious coalition together.

The coalition is composed of Anwar’s Parti Keadilan Rakyat, made up mostly of urban, moderate ethnic Malays; Parti Islam se-Malaysia, a fundamentalist Malay Muslim party with rural roots; and the Democratic Action Party, which is primarily ethnic Chinese. It came together in the immediate wake of the 2008 general election after the three parties gained control of five state assemblies and made significant gains at the federal level, denying the national ruling coalition a two-thirds majority in the parliament.

The coalition hit its high point in the 13th general election in May 2013, winning an absolute majority of the national vote with 50.87 percent to 46.38 percent for the Barisan. However, gerrymandering and the first-past-the-post electoral system gave the Barisan 133 seats compared to 89 for the opposition. That is increasingly looking like the crest of he opposition wave, especially if Anwar, 66, goes to jail.

The strains between three such dissimilar parties have made for disruptive politics for six years. But now the coalition could splinter over what appears to be a parochial matter – the leadership of Selangor.

In March, Anwar decided to replace chief minister Khalid Ibrahim of Parti Keadilan, allegedly for showing lackluster leadership. Anwar then engineered the resignation of seat-holder Lee Chin Cheh in a Kuala Lumpur suburb to create a vacancy that he hoped to fill in a by-election.

Anwar’s plans were blocked when the appellate court rushed through the guilty verdict. The verdict, now on appeal to the country’s Federal Court, disqualified him from running for the seat as a convicted felon. His wife, Wan Aziza Wan Ismail, ran instead and won. The plan was to install her as chief minister.

It didn’t work. Khalid Ibrahim found an unlikely ally in PAS leader Abdul Hadi Awang, who would ultimately like to make Parti Keadilan vice president Azmin Ali the chief minister. While Azmin is a member of Anwar’s party, the two are rivals. The DAP backs Anwar. In order to decide who gets the job, it might require a state snap election, which the national ruling coalition might win.

While the chief minister battle is the focal point, the coalition has long-faced deeper strains between PAS and its moderate partners, Parti Keadilan and the DAP.

Neither urban Malays nor the Chinese in the DAP want anything to do with PAS’s continuing efforts to push through hudud for the state of Kelantan, which it controls. Hudud is a medieval system of punishment under Islamic religious law that would include the amputation of limbs for minor crimes and stoning for adultery. The two parties fear that passage in Kelantan could spread to other Malay-majority states, eventually being applied even to non-Muslim Malaysians.

UMNO has skilfully played the divisions between the parties, particularly over the hudud issue. Although it would be unheard of for an opposition party to be allowed to introduce a private member’s bill in parliament, the PAS hudud proposal was quickly steered to a committee for study, thus keeping it alive.

Now the question comes down to whether the fear of a resurgent Barisan will be enough to keep the warring opposition elements together for the broader goal of one day controlling the national government.