In the weeks leading up to the US midterm elections, the message from Fox News was clear: violent crime is surging, cities are dangerous hellscapes and Democrats are responsible.

With the vote over, however, the rightwing news channel appeared to decide things weren’t that bad after all, and decreased its coverage of violent crime by 50% compared with the pre-election average.

Media Matters for America, a media watchdog, found that each week from Labor Day until the Friday before the Tuesday 8 November vote, the network averaged 141 segments on crime across weekdays. The blanket crime coverage matched the Republican party’s efforts to depict violent crime as out of control, and portray Democrats as responsible.

In the week of the midterms, however, once voting was over, Fox News aired just 71 segments on violent crime, Media Matters reported.

“I think this shows pretty clearly that the amount of Fox coverage of violent crime doesn’t really have anything to do with the level of violent crime in America – it has to do with the political benefits,” said Matt Gertz, a senior fellow at Media Matters.

“It crescendoed right before election day, and then once the election was over, so was America’s crime crisis no longer the subject of maximum concern that it had been in the previous weeks.”

Media Matters noted that Fox News crime coverage had increased somewhat in recent days after the shooting at the University of Virginia and the student killings in Idaho, but said “the coverage was notably less focused on painting Democratic cities as crime-infested”.

Fox News declined to comment.

Gertz said Tucker Carlson, Fox News’ most-watched host, had a big part to play in the coverage – and in how Republicans across the country used crime as an issue. In a monologue in August, Carlson advised Republican politicians to focus their campaigns on “law and order”, which he said would result in a “red wave” in the midterms.

Republicans did just that, spending millions on ads which highlighted instances of violent crime and portrayed Democrats, like John Fetterman, running for US Senate in Pennsylvania, as responsible. The Washington Post reported that Republicans spent nearly $50m on ads focused on crime between 5 September and 25 October, far outspending Democrats on the issue.

The network’s focus on a singular issue in the lead-up to an election is nothing new, Gertz said. He said ahead of the 2014 midterm elections the Ebola outbreak became a repeated issue on Fox News, with the network blaming Barack Obama for the spread of the virus.

In 2016 Hillary Clinton’s emails became the hot topic, while in 2018 Fox News picked up on a so-called “migrant caravan”, using it to bolster Donald Trump’s midterm election sell that the country needed to elect more Republicans to enact tougher immigration laws.

“It’s a play that they’ve run over and over again in elections over the past decade,” Gertz said.

“Fox does this every time they come up with some sort of message that they want to push, and they try to get Republicans to adopt it, and they try to get the mainstream press to adopt it as well,” he added.

“And so the question becomes: to what extent is the mainstream press going to take the bait and turn it into a multiplier effect – where they are repeating Fox’s message and the debate in the final days of the elections is turning on whatever Fox wanted to talk about?”

It seems this time neither the mainstream media nor voters took the bait.

Carlson’s “red wave” failed to materialize in the midterm vote, as Republican candidates largely underperformed expectations.

Fetterman, the target of repeated attacks by Fox News and numerous crime ads from his opponent, Mehmet Oz, won his race by almost 5%, and while having been predicted to make significant gains in Congress, Republicans only narrowly took control of the House, and Democrats retained the Senate.