Rupert Murdoch’s Fox Corporation on Monday filed a motion to dismiss the $2.7 billion defamation lawsuit brought against it last week by the election technology company Smartmatic, which has accused Mr. Murdoch’s cable networks and three Fox anchors of spreading falsehoods that the company tried to rig the presidential race against Donald J. Trump.

The lawsuit has roiled right-wing news media outlets whose star personalities repeatedly cast doubt on Joseph R. Biden Jr.’s victory in the wake of the election and raised the specter of a significant financial penalty for Fox. On Friday, the day after the lawsuit was filed, Fox canceled the nightly Fox Business program hosted by Lou Dobbs, who is named in the suit along with the Fox anchors Maria Bartiromo and Jeanine Pirro.

In its 44-page response filed in New York State Supreme Court, Fox argues that the claims of electoral fraud made on its channels by Mr. Trump’s lawyers — including Rudolph W. Giuliani and Sidney Powell, who are also named in the defamation suit — were matters of significant interest to viewers and handled fairly.

“This lawsuit strikes at the heart of the news media’s First Amendment mission to inform on matters of public concern,” Fox says in the motion, adding, “An attempt by a sitting president to challenge the result of an election is objectively newsworthy.”

Paul D. Clement, a partner in the Washington office of the law firm Kirkland & Ellis who served as solicitor general under President George W. Bush, is leading Fox’s defense. “Smartmatic’s theory is fundamentally incompatible with the reality of the modern news network and deeply rooted principles of free speech law,” Mr. Clement said in a statement.

A spokesman for Smartmatic did not immediately reply to a request for comment.

“It’s a strong move on their part to try to come out and dismiss the claim,” said Timothy Zick, a professor at William & Mary Law School who specializes in First Amendment law.

Mr. Zick said that Fox was making use of the concept of “neutral reportage,” arguing that it could not be sued for defamation while covering the news. “They’re arguing that shields Fox News as an organization for simply reporting on the controversy, which is a matter of public interest,” he said.

A key to Fox’s defense is the argument that it cannot be held responsible for statements made on its programs by Mr. Giuliani and Ms. Powell, given their roles as Mr. Trump’s legal representatives.

“The public had a right to know, and Fox had a right to cover, that the president and his allies were accusing Smartmatic (and others) of manipulating the election results, regardless of the ultimate truth or accuracy of those allegations,” the motion reads. It also asserts that Smartmatic’s suit does not identify defamatory statements by television hosts employed by Mr. Murdoch’s company.

Fox also argues that Smartmatic should be considered a public figure. That argument, which is likely to be contested by the tech company, means that Smartmatic must meet a high bar to prove that it was defamed: demonstrating that the defendants knew their statements were false, or at least had serious doubts about them.

Smartmatic’s 276-page lawsuit alleges that Mr. Trump’s lawyers used Fox’s platform, and its sympathetic anchors, to spin conspiracies about the company that damaged its reputation and commercial prospects. The suit has been applauded by those seeking to curb the flow of disinformation from right-wing news outlets, but it has also raised questions about the limits of speech in a changing media landscape.

Fox’s argument in its motion — that it provided a forum for newsworthy interviews — may cut into the conceptual heart of Smartmatic’s case, which groups Fox, its hosts and their guests as defendants who collaborated to spread falsehoods.

The defamation lawsuit cites exchanges on Fox programs that, Smartmatic said, helped spread the false claim that it was the owner of a rival election tech company, Dominion Voting System, and that it provided its services to districts in multiple contested states. In fact, Smartmatic was used in the 2020 election only by Los Angeles County.

And Smartmatic offers vivid examples of Fox programming that spread bizarre falsehoods, like a claim by Ms. Powell made on Mr. Dobbs’s show that the former president of Venezuela, Hugo Chávez, had assisted the company in creating software that could covertly alter votes. (Mr. Chávez died in 2013 and had nothing to do with Smartmatic.)

In other exchanges cited by Smartmatic, Fox anchors alternately expressed support and astonishment as Mr. Giuliani and Ms. Powell spun out their claims. In one case, a phrase used by Ms. Powell — “cyber Pearl Harbor” — was later invoked by Mr. Dobbs on his show and on social media.

Fox’s response on Monday included a 14-page appendix under the title “Fox’s Evenhanded Coverage of Smartmatic,” documenting instances from Fox News and Fox Business that the company believes showed skepticism toward the Trump team’s claims.

Among the examples are three identical, pretaped fact-checking segments that ran in mid-December on programs hosted by Ms. Bartiromo, Mr. Dobbs and Ms. Pirro and that featured Eddie Perez, an election expert who debunked a number of false claims about Smartmatic.

The segments were broadcast after Smartmatic sent a letter to Fox demanding retractions and threatening legal action.