KUALA LUMPUR, Malaysia (AP) — Malaysian opposition icon Anwar Ibrahim can't vote in what he believes will be a "defining election" for his country on Wednesday but even from his prison cell has remained a political force to be reckoned with.

The firebrand politician's conviction in 2015 for what he and his supporters said were false allegations of sodomy fractured the alliance of opposition parties that under Anwar's leadership was threatening the ruling National Front's decades-long hold on power.

It was Anwar's second spell in prison and it seemed he'd finally been done in by dirty political tactics. Once a high flyer in the ruling party, in 1998 he was convicted of homosexual sodomy — a criminal offense in Muslim-majority Malaysia inherited from the British colonial era — and corruption following a power struggle with Mahathir Mohammad, Malaysia's authoritarian prime minister for more than two decades.

Anwar, however, played an unexpected card. From prison he helped forge a new opposition alliance by ending the two-decade feud with his former persecutor-in-chief, Mahathir, who'd once called Anwar "morally unfit" to govern the country.

It was a hard but pragmatic decision, Anwar's eldest daughter, lawmaker Nurul Izzah Anwar, told The Associated Press.

Anwar, 70, is an "incorrigible optimist" who believes there must be sacrifices to bring about a change of government and badly needed reforms, she said.

"He was instrumental in galvanizing an eventual approval to get Mahathir to be part of our coalition," said Nurul Izzah. "He was the first to state that it's time for us to be actively playing our part to design the Malaysia that we want."

Mahathir, 92, now leads an opposition alliance that includes Anwar's party. They're campaigning to oust Prime Minister Najib Razak, who is mired in scandal, and end the National Front's unbroken 60-year rule.

Even with Mahathir, who is popular with Malaysia's Malay majority, the odds are stacked against the opposition. It won the popular vote in 2013 but the ruling party clung to a majority in Parliament because of an electoral system that gives more weight to Malay-dominated rural seats that traditionally support the government.

A popular Islamic student leader, Anwar joined the ruling Malay party in 1982, a year after Mahathir became prime minister. He quickly rose up the ranks, becoming finance minister in 1991 and deputy premier two years later. Anwar became the heir apparent to Mahathir but they fell out during the 1998 Asian financial crisis and Anwar was sacked.

He refused to go quietly, leading tens of thousands of demonstrators in street rallies in Kuala Lumpur demanding reforms before he was arrested. He was later produced in court with a black eye from a beating by the police chief. That black eye has become the logo of the People's Justice Party led by his wife and is now the symbol of the opposition challenge against Najib.

Anwar was freed in 2004 after Mahathir retired and cleared of the sodomy charges.

In 2008 elections, his opposition pact known as the People's Alliance made major inroads by depriving the National Front of a two-thirds majority in Parliament for the first time. In 2013, the National Front lost the popular vote, its worst result since independence from Britain in 1957. It currently holds 132 of 222 seats.

But in 2015, Anwar was imprisoned again after new allegations of sodomizing an aide that he and his supporters said was a government plot to crush the opposition.

"Authoritarian leaders always believe the best way to deal with dissidents is to jail them, but throughout history, it has always backfired," Anwar said at the time.

His opposition alliance broke up after its Islamist ally left. It regrouped as the Alliance of Hope but the pact was shaky due to infighting and the lack of a charismatic figure to hold it together day to day.

Mahathir's political comeback in 2016 provided the missing glue. Despite his advanced age, Mahathir was seen as the best chance for the opposition to win support from rural Malays.

The former prime minister was spurred out of retirement by the corruption scandal at 1MDB, a state fund that is being investigated by the U.S. and several other countries after associates of Najib allegedly stole and laundered $4.5 billion from it. The fund was set up by Najib in 2009 to promote economic but accumulated billions in debts.

In September 2016, Mahathir met Anwar for the first time in 18 years. Social media was awash with pictures of the two men shaking hands and chatting in court, where Anwar was challenging a repressive new security law.

An opposition victory in the election, though unlikely, could result in a spectacular comeback for Anwar.

He is due to be released from prison on June 8 and Mahathir has pledged to hand leadership to him. Officials say Anwar could take power with a royal pardon.

Anwar, said Nurul Izzah, "knows it's a defining election, he knows the stakes are high."

"We have to face a lot of onslaught against Mahathir especially in the lead-up to the election, but we are also saying that we are not apologists. Like it or not, he is now doing his bit at the age of 92, what are you doing about it? That's the key message we are giving out."