The California Senate is expected to debate punishment for a lawmaker accused of sexual misconduct Thursday, including what could be the first expulsion in more than a century. The highly unusual session comes a day after Republicans and Democrats met separately in secret caucus meetings to decide the appropriate discipline for Sen. Tony Mendoza, who plans to defend himself on the Senate floor. Lawyers investigating complaints against Mendoza, who is 46 and married, found that he likely engaged in unwanted 'flirtatious or sexually suggestive' behavior with six women, including four subordinates, a lobbyist and a young woman in a fellowship with another lawmaker. Several accusations against Mendoza first became public last fall in a report by the Sacramento Bee. Under pressure from other lawmakers, Mendoza took a leave of absence. The Senate Rules Committee suspended him in late January — days before he was set to return from leave — because the independent investigation had not yet concluded. Mendoza sued for reinstatement last week alleging, among other arguments, that the suspension was unconstitutional. The California Constitution requires a two-thirds vote to suspend a member, but the chamber voted last month to give the five-member Rules Committee the power to extend Mendoza's leave of absence. In a letter pleading his case to colleagues Wednesday, the Los Angeles-area Democrat said he was sorry if anyone was offended by his behavior but continued to deny wrongdoing. The investigation, which was released Tuesday, found Mendoza 'more likely than not' engaged in behavior such as offering a 19-year-old intern alcohol in a hotel suite at a Democratic Party event, suggesting a young woman in a Senate fellowship take a vacation with him and rent a room in his house, and asked several of the women about their dating lives. Expelling or suspending Mendoza would require a two-thirds vote — 27 of the 40 senators. He can be censured with 21 votes. No senator has been expelled since 1905, and the Senate has suspended just three members — Leland Yee, Ron Calderon and Roderick Wright — all of them in 2014 when they faced criminal charges. 'You always go back to the most important point: You have to be fair but you have to put the institution first. That is always the touchstone,' said Darrell Steinberg, who was the Senate's leader when the chamber dealt with the charges against Yee, Calderon and Wright. He is now Sacramento's mayor. The California Constitution at the time said lawmakers could lose their pay only if they were expelled or resigned, though an amendment later approved by voters allowed suspension without pay. Mendoza warned that it would set a dangerous precedent to expel him — a punishment he said has been previously meted out only for lawmakers who have committed a crime. 'It is important to note that the voters in my district have information, now that the investigation results are public, that they can use to make a decision whether they should re-elect me this year, as early as June 2018,' Mendoza wrote to lawmakers. He repeated his complaint that the Senate has not followed its own process for disciplining lawmakers and that he hasn't been allowed to read the full investigative report, including the evidence against him. The summarized findings released late Tuesday 'do not comport with my recollection or perception of the events described,' Mendoza wrote, but added: 'I am immensely sorry if my words or actions ever made anyone feel uncomfortable.' Mendoza's letter specifically denied giving alcohol to an underage intern or inviting a young aide, who worked in his office through a California State University fellowship, to his house under the guise of reviewing resumes. He did not directly address the investigation's other findings. He also pointed out that the investigators found no instances of Mendoza being physically aggressive or sexually crude, and that in some of the incidents he reformed his behavior after he was told his advances were unwanted. The California Legislature is one of many statehouses nationwide grappling with a tidal wave of sexual misconduct allegations following the #MeToo movement in which millions of women shared their experiences with sexual harassment or assault on social media. Mendoza, who was chairman of the Insurance, Banking and Financial Institutions Committee until the allegations came to light last year, is the first member of the Senate to face punishment since the sexual misconduct scandal emerged last fall. Assemblywoman Cristina Garcia, who represents a portion of the district Mendoza was elected to serve, took a voluntary leave after she was accused of groping. Two other Los Angeles-area Assembly Democrats — Raul Bocanegra and Matt Dababneh — resigned their seats.