The full review is set to be released on Friday, but draft versions circulating through Arizona political circles were obtained by The New York Times from a Republican and a Democrat.

Late on Thursday night, Maricopa County, whose Republican leaders have derided the review, got a jump on the official release by tweeting out its conclusions.

“The county’s canvass of the 2020 General Election was accurate and the candidates certified as the winners did, in fact, win,” the county said on Twitter.

Biden won Arizona by roughly 10,500 votes, making his victory of about 45,000 votes in Maricopa County crucial to his win.

One expert and critic of the review who had seen a draft report of the findings called those red herrings.

“The whole report just reflects on the Ninjas’ lack of understanding of Arizona election law and election administration procedures,” said Benny White, a Republican in Tucson who is an adviser on election law and procedures.

On Thursday night, without acknowledging the findings of the draft reports that had been rippling across Arizona for half a day, the former president said in a statement, “Everybody will be watching Arizona tomorrow to see what the highly respected auditors and Arizona State Senate found out regarding the so-called Election!”.

Election experts said the inquiry run by Trump partisans with unrestricted access to ballots and election equipment failed to make even a basic case that the November vote was badly flawed, much less rigged.

The Republican president of the State Senate, Karen Fann, insisted that the review was a nonpartisan effort to reassure voters that the election had been well run, but faith in that pledge ebbed after she chose Cyber Ninjas, a firm with no prior experience in elections, to oversee the inquiry.

While the report’s authors declared that their monthslong review of votes in Maricopa County represented the “most comprehensive and complex election audit ever conducted,” the hand count of 2.1 million ballots and a review of voting machines and systems was plagued from the start by missteps and accusations of incompetence and partisan influence.

Some elections officials said the draft reports offered an unlikely vindication of what they have been insisting for months: that Arizona ran a transparent, credible election in November.

“The numbers match up,” said Adrian Fontes, who as county recorder oversaw the election in Maricopa County and is now a Democratic candidate for secretary of state.

The report takes an extended look at marker bleed-through on ballots, which was the source of a debunked conspiracy known as #Sharpiegate that claimed ballots filled out with a felt-tipped pen could not be read by machines in Arizona.

Election experts pointed to the corrosive effect of the decision to stage a partisan review of the election results, with copycat versions in other states and further eroding trust in democratic institutions.

Reputable election experts have said for months that the Senate review would be wrong if it concluded that Mr.

Trump lost Arizona because 74,822 Republicans, including 59,800 in Maricopa County, were unhappy enough with the former president’s performance in office that they decided not to vote for him.

The Republican who is now Maricopa County’s chief election officer, Stephen Richer, published a 38-page broadside last month in which he rebutted fraud claims and excoriated Republican politicians who have remained silent in the face of efforts to undermine the November results