Eight months after the 2020 election, a key Pennsylvania Republican lawmaker is heeding former President Donald Trump’s demands for investigations into his false claims of fraud.

State Sen. Doug Mastriano, a likely gubernatorial candidate and a leading election denialist in the state, sent letters Wednesday to multiple counties seeking election-related equipment and materials “needed to conduct a forensic investigation” of the 2020 election and the 2021 primary.

Mastriano sent the letters to Philadelphia, York, and Tioga Counties, he said Wednesday. “We’re looking at three counties, and if sufficient evidence comes up with shenanigans and corruption or fraud, then we’ll have a second round with additional counties,” he said on the pro-Trump cable network OAN.

Philadelphia officials confirmed the city received a letter but declined to comment further on the requests.

Mastriano’s requests are sprawling and include essentially all election-related materials, such as ballots, mail ballot applications, mail ballot envelopes, voting machines, ballot scanners and vote-counting equipment, ballot production equipment, poll books, and computer equipment used throughout the election process.

The letters warn that the Senate committee Mastriano leads may issue subpoenas if counties don’t respond by July 31 with a “plan to comply.”

It’s not clear how Mastriano’s investigation would work. Basic questions that were unanswered Wednesday included where equipment and ballots would be stored securely, who would be involved and have access, what training those people would have, what standards and procedures they would follow, and what documentation would be required during the review.

Depending on what Mastriano is looking for, it may also be too late: Election equipment is reused, so voting machines used at polling places in 2020 were reprogrammed for the May primary.

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The push comes after Mastriano and two other Pennsylvania GOP lawmakers traveled to Arizona last month for a firsthand look at the widely criticized partisan “audit” in Maricopa County. That months-long review has been led by a contractor with no previous experience auditing elections and whose CEO amplified Trump’s false claims.

Mastriano said his investigation will model the Arizona review. “It’s much of what we saw in Arizona, which really set the standard on a forensic analysis,” he said on OAN.

Pennsylvania already conducted a “risk-limiting” audit in 63 of its 67 counties. Counties are also required by law to audit a sample of ballots. There is no evidence of significant fraud in Pennsylvania’s election.

Mastriano is widely expected to run for governor in next year’s open-seat race to succeed Democratic Gov. Tom Wolf, who is term-limited.

A Mastriano-led investigation is almost certain to prompt legal challenges from Democratic-led counties or state Attorney General Josh Shapiro, a Democrat and likely candidate for governor who has said he would seek to block an Arizona-style review.

“[S]hould subpoenas be issued, you can expect our office to do everything to protect the Commonwealth, its voters, and the free, fair election that was held in Pennsylvania,” Shapiro tweeted Wednesday. He called on counties to “refuse to participate in this partisan fishing expedition.”

It remains to be seen how the three counties will respond. Philadelphia elections officials pushed back on the claims Mastriano made in his letter. Nick Custodio, a deputy under city elections chief Lisa Deeley, said in a statement that “the repetition of baseless claims by elected officials poses a real challenge to our democratic processes.”

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Mastriano’s requests would significantly disrupt any county elections office and likely make it difficult to run November’s election. Election preparation begins long before the first vote is cast, and if a review takes months, like in Arizona, that could prevent a county from using its equipment.

It could also render equipment unusable in the future. Unless specific chain-of-custody protocols are followed and access is limited, it’s considered a major security vulnerability to give third parties access to election equipment. In Arizona, Maricopa County will buy new equipment after its review. And in Pennsylvania, Fulton County already had to get new voting machines after an audit that Mastriano had a hand in.

That audit was funded by a nonprofit led by former Trump lawyer Sidney Powell, a prominent election conspiracy theorist.

It remains to be seen how Mastriano’s investigation would be funded. Senate Republican leaders have ruled out using taxpayer money, and Mastriano led a private briefing last week with his caucus to discuss the possibility of seeking private funding for the probe, the Associated Press reported.

Republicans have railed against private funding in elections after some large counties, including Philadelphia, received grants last year. Arizona’s review is being privately financed, and officials there haven’t disclosed the source of funding.

Not all Pennsylvania Republicans are on board with Mastriano’s plan. State Rep. Seth Grove (R., York), House Republicans’ point person on election issues, has said he opposes the idea.

But an investigation threatens to plunge the GOP into months of 2020 revisionism and further alienate swing voters. That could have implications both for the governor’s race and Pennsylvania’s high-stakes U.S. Senate election in 2022.

It would also almost certainly create more confusion around the 2020 election and suspicion of Pennsylvania’s election system generally, despite Mastriano’s claim that an investigation would calm public distrust.

“A full forensic investigation is critically necessary for our Commonwealth for the sake of transparency and accountability. There is nothing to fear if there is nothing to hide,” Mastriano said in a statement. “Those who have concerns about the integrity of the 2020 and 2021 election will have those concerns investigated and hopefully addressed. Those who think that there was zero voter fraud, no irregularities, and that the elections were conducted perfectly will have the chance to be vindicated.”

The concerns about election integrity have been largely driven by Trump’s election lies — and Republicans’ amplification of them.

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Two top Senate Democrats asked Republican leaders to step in and stop Mastriano, calling the review an “unlawful witch hunt.”

”This is nothing more than an attempt to appease the disgruntled supporters of former President Donald Trump and serve as a campaign vehicle for Senator Mastriano to advance his run for Governor,” Senate Minority Leader Jay Costa (D., Allegheny) and Sen. Anthony H. Williams (D., Philadelphia), the minority chair of the Intergovernmental Operations Committee, wrote Wednesday in a letter to top Senate Republicans.

”We urge you to issue a cease and desist order for this member of the chamber before he does even more damage to the credibility of government institutions,” they wrote. “His behavior over the last six months has eroded the integrity of the State Senate and it must be stopped.”

Mastriano, a retired Army colonel from Franklin County in south-central Pennsylvania, has amplified conspiracy theories about President Joe Biden’s electoral victory and met with Trump personally in New York this spring. He traveled to Washington for the Jan. 6 rally that preceded the Capitol attack, and paid for buses to take other Trump supporters.

Mastriano has said he left the Capitol area before rioters stormed the building, but video evidence unearthed by online sleuths in May appears to show he stuck around longer and got closer to the Capitol than he has previously acknowledged.