Rudolph W. Giuliani, Mark Meadows, and a number of others who advised Donald J. Trump during the 2020 election were indicted in Arizona on Wednesday, along with all of the fake electors who acted on Mr. Trump’s behalf there to try to keep him in power despite his loss in the state.

Boris Epshteyn, one of Mr. Trump’s top legal strategists, was also among those indicted, a complication for Mr. Trump’s defense in the criminal trial that began this week in Manhattan over hush money payments made to a porn star, Stormy Daniels.

The indictment includes conspiracy, fraud and forgery charges, related to alleged attempts by the defendants to change the 2020 election results. Arizona is the fourth swing state to bring an elections case involving the activities of the Trump campaign in 2020, but only the second after Georgia to go beyond the fake electors whom the campaign deployed in swing states lost by Mr. Trump.

The former president was also named an unindicted co-conspirator in the Arizona case.

“I understand for some of you today didn’t come fast enough, and I know I’ll be criticized by others for conducting this investigation at all,” Kris Mayes, Arizona’s Democratic attorney general, said in a recorded statement. “But as I have stated before and will say here again today, I will not allow American democracy to be undermined. It’s too important.”

Mr. Giuliani is Mr. Trump’s former personal lawyer; Mr. Meadows was the White House chief of staff at the time of the 2020 election. They were among a number of defendants whose names were redacted from the indictment, though it was clear from the context and the descriptions who they were. For example, the passage referencing Mr. Giuliani, the former mayor of New York City, said among other things that he was known as “the mayor.”

Some parts of the indictment did not refer to Mr. Trump by name, instead referring to the “defendants’ attempts to declare Unindicted Coconspirator 1 and Pence the winners of the 2020 Presidential Election.”

Also indicted were Mike Roman, a Trump campaign operative in 2020, John Eastman, an architect of the fake electors plan, and two other lawyers who advised Mr. Trump and his 2020 campaign: Jenna Ellis and Christina Bobb.

In all, 35 people who acted as fake electors in Georgia, Michigan, Nevada and now Arizona face criminal charges for signing certificates in 2020 falsely stating that Mr. Trump had won their state’s electoral votes.

Mr. Giuliani, Mr. Meadows, Mr. Roman and Mr. Eastman now face charges in two states, Georgia and Arizona. Ms. Ellis has already pleaded guilty to a felony in Georgia.

Among those charged are some who served as top Republican Party officials in Arizona during the 2020 election, including Kelli Ward, a former state party chairwoman, and Greg Safsten, who at the time was executive director of the state party. Two state senators, Anthony Kern and Jake Hoffman, now also face charges.

Some of the people who held themselves out to be Trump electors in states that he lost in 2020 have adamantly insisted that they were acting legally. After Dr. Ward and other fake electors gathered in Phoenix that December, she wrote in a social media post that “we are the electors who represent the legal voters of Arizona!” As recently as late last year, Mr. Kern said that “there’s no such thing as fake electors.”

Late Wednesday, Charles Burnham, a lawyer for Mr. Eastman, said: “The phenomenon of partisan lawfare grows more troubling by the day. Professor Eastman is innocent of criminal conduct in Arizona or any other place and will fight these charges as he has all the other unjust accusations leveled against him.”

Ted Goodman, a spokesman for Mr. Giuliani, said: “The continued weaponization of our justice system should concern every American as it does permanent, irrevocable harm to the country.”

Mr. Hoffman said in a social media post that he was “innocent of any crime,” adding that “I will vigorously defend myself, and I look forward to the day when I am vindicated of this disgusting political persecution.”

Mr. Epshteyn was a constant presence during Mr. Trump’s civil trial in January on charges that he had defamed the New York writer E. Jean Carroll. He joined Mr. Trump at the defense table when Mr. Trump’s lawyer in the case went to the bench for sidebars.

But Mr. Epshteyn has not been in New York for the current criminal case. He has described himself as an “in-house counsel” to Mr. Trump and has been something of a quarterback for the various legal teams working on the former president’s defenses in four criminal cases. He usually speaks with Mr. Trump several times a day.

Mr. Epshteyn has been arrested twice in Arizona over the last 10 years, once in 2014 for assault after a bar fight, in which he pleaded guilty and the conviction was set aside, and again in 2021, after he was accused of inappropriately touching two women. In that case, he pleaded guilty to disorderly conduct, received probation and a fine, and the conviction again was set aside.

Mr. Epshteyn did not immediately respond to a request for comment.

Election deniers have not fared well at the polls in Arizona, but they maintain a grip on the state’s Republican Party. In January, the party installed a hard-right Trump supporter, Gina Swoboda, as its new leader; Ms. Swoboda runs a nonprofit group that has falsely claimed to have found huge discrepancies in voting records in a number of states. Kari Lake, a fervent backer of Mr. Trump and his false election claims, was the party’s candidate for governor in 2022 (she lost) and is the leading Republican candidate for a U.S. Senate seat this year.

The United States Supreme Court rejected an appeal on Monday that challenged the state’s electronic voting machines. The case was brought by Ms. Lake and Mark Finchem, who lost a 2022 race for Arizona secretary of state.

Having slates of people claiming to be electors for Mr. Trump was an integral part of the effort to keep him in office after his loss at the polls in 2020. Mr. Trump and his allies sought to block or delay congressional certification of Joseph R. Biden Jr.’s victory, hoping that Mr. Trump’s allies in the House and Senate might then consider a challenge to the validity of the results in a number of battleground states like Arizona and Michigan — and then accept the pro-Trump electors from those states as valid.

In addition to the state cases, Mr. Trump is facing election interference charges himself in the Georgia case and in a federal case brought by Jack Smith, the special prosecutor appointed by the Department of Justice.

Mr. Trump has long made a strategy of falsely claiming election fraud. After he was defeated in the 2016 Iowa caucus, he said that Senator Ted Cruz of Texas, the winner of that contest, “illegally stole it.” And after Mr. Trump received fewer votes nationwide in 2016 than Hillary Clinton idid, he said that he had actually won the popular vote “if you deduct the millions of people who voted illegally.”

Faced with criminal charges in the state elections inquiries, some of Mr. Trump’s allies and advisers have backtracked from his 2020 claims.

“Biden was elected, the process was followed,” Kenneth Chesebro, an architect of the fake elector plan, told investigators in Michigan last year. Mr. Chesebro has emerged as a key witness in the state prosecutions.

James Renner, a former Michigan state trooper who was a last-minute substitution as a fake elector in that state, expressed regret last year to investigators, saying that he “had been walked into a situation that I shouldn’t have ever been involved in.” Charges against him were dropped as part of a cooperation agreement with the office of Dana Nessel, Michigan’s attorney general, a Democrat.

Richard Fausset, Alan Feuer, Jonathan Swan and Benjamin Protess contributed reporting.