HARRISBURG — State Sen. Doug Mastriano is facing an ethics complaint from a Philadelphia-area Democrat who alleges the right-wing lawmaker violated the state and U.S. constitutions when he used his prominent role as a state senator to try to overturn the 2020 election results.

State Sen. Art Haywood, a Democrat representing parts of Philadelphia and Montgomery counties and outspoken critic of former President Donald Trump, announced Tuesday he will next week file an ethics complaint asking the state Senate’s ethics committee to investigate Mastriano’s role in trying to overturn Pennsylvania’s 2020 election.

Haywood’s complaint is based on an April 2023 report from Citizens for Responsibility and Ethics in Washington, a watchdog group which has called for Trump’s disqualification from holding office. The report details Mastriano’s role in trying to overturn Pennsylvania’s 2020 election results, including hosting a November 2020 Pennsylvania Senate hearing with unsworn testimony from Trump attorney Rudy Giuliani and other advisers, his presence on Capitol grounds during the Jan. 6, 2021 attack on the U.S. Capitol, and more.

“The Senate is a place of integrity, and this complaint is to uphold that integrity,” Haywood said. “The Senate as an institution should be continued to be respected, and this is an investigation where the conclusions haven’t been reached.”

Mastriano, R-Franklin, first rose to popularity in Pennsylvania in 2020 at the start of the COVID-19 pandemic, as a leader of resistance efforts to government shutdowns to slow the spread. That popularity continued to grow heading into the 2020 election, as he stepped into the role as one of former President Donald Trump’s top advocates in the battleground state asking that the state’s election results be overturned due to disproven fraud claims.

Mastriano has remained a fixture in Pennsylvania’s Republican Party since then, which helped him receive the party’s nomination as its gubernatorial nominee in 2022. He lost that election by about 14 percentage points, and briefly considered running for U.S. Senate. He continues to have a national following, particularly among Christian nationalists.

The Senate ethics committee is rarely used or even formed, Haywood said in an interview after his announcement. But the seriousness of Mastriano’s actions requires the state Senate to take action, he added.

Haywood said he chose to use this rare and serious mechanism over other options, such as impeachment, because multiple outcomes can be reached — the most serious of which is expulsion. Other outcomes include reprimand or censure that Haywood said he believes should be considered.

Brie Sparkman, policy counsel at CREW, said Mastriano’s continued service in the state Senate “threatens the peoples continued faith in democracy.”

Once the complaint is officially filed this week, the president pro tempore of the Senate — the top lawmaker of the chamber — will be tasked with appointing three members from each party to serve on the committee. A spokesperson for President Pro Tempore Kim Ward, R-Westmoreland, declined to comment and referred to the Senate rules about its procedures.

A spokesperson for Senate Majority Leader Joe Pittman, R-Indiana, said in a statement that any ethics complaints will be reviewed thoroughly per Senate rules, adding, “It is unfortunate we are seeing the new year start with political gamesmanship.”

According to Senate rules, once the committee is formed, the members will review the complaint within 30 days and decide whether a preliminary investigation is necessary.

Mastriano, whose birthday was Tuesday, did not respond to a request for comment.