Malaysian authorities on Wednesday summoned opposition leader Anwar Ibrahim to court to face a sodomy charge, complicating his bid to return to Parliament in a by-election less than three weeks away.

It will be the second time in a decade that the former deputy prime minister has been charged with sodomy, a crime that carries a maximum penalty of 20 years in prison. Sodomy is illegal even among consenting adults in Muslim-majority Malaysia.

A 23-year-old male aide claimed Anwar had sodomized him in June. Anwar insists the allegation was fabricated to thwart his plan of seizing power from the government by mid-September. The government denies a conspiracy.

If the court refuses to release Anwar on bail pending a trial, it would prevent him from campaigning in the Aug. 26 by-election for a parliamentary seat that his wife vacated last week. Anwar would still be allowed to contest the seat.

Anwar’s attorney, Sankara Nair, said the police letter informed Anwar that he must come to court “to answer charges,” though no details were provided.

National deputy police chief Ismail Omar said in a statement the attorney general’s office had decided to charge Anwar after police “completed their investigation into a criminal sex case involving intercourse against the laws of nature.”

Anwar will face a challenger from Prime Minister Abdullah Ahmad Badawi’s ruling coalition. Analysts have forecast that Anwar will win because the constituency has been his stronghold since the early 1980s, including nearly two decades when he was in the government. He was ousted as deputy prime minister in 1998 and imprisoned over accusations that he sodomized his driver and abused his power to cover up the offense.

A court quashed the sodomy conviction and freed him in 2004, but the corruption conviction barred him from office until April 2008. Anwar denied the charges and has waited since then to re-enter Parliament.

Nearly 58,500 voters are eligible to cast ballots in Permatang Pauh. Nominees will file candidacy papers Aug. 16 and have 10 days to formally campaign, the Election Commission said.

The commission urged both sides to “obey the instructions of the security officials to safeguard public safety and security.”

Anwar, a former deputy prime minister who is now the opposition’s most charismatic figure, has said he expects the government to spend massive sums bribing voters to defeat him. Authorities have dismissed the claims, saying they are committed to fair elections.

Anwar is at the center of political turbulence that began in March when the ruling National Front coalition retained its power but lost its long-held two-thirds parliamentary majority control of five of Malaysia’s 13 states.

The coalition has a 30-seat majority in the 222-member Parliament but Anwar has said he can persuade enough lawmakers to switch sides to bring down the government by Sept. 16.