With the start of Congressional primary elections at hand, candidates are highlighting China in their campaign advertising to tout that either that they’re tough on China, or that their opponents are too cozy with the communist nation.

Experts on China and on election campaigns said the themes are popular for one significant reason: China is unpopular with Americans, whether because they view it as an economic or security threat, or whether they blame it for the COVID-19 pandemic.

"Nobody likes China, so there's no risk of offending anyone or losing any votes," said James Andrew Lewis, a senior vice president at the Center for Strategic and International Studies. He cited China’s repression of Uyghur Muslims, threats against Taiwan and Hong Kong, and espionage in the United States. 

"And China's an easy target since it is the biggest national security issue we face. Can't go wrong on China bashing," he said.

Both the be-tough and the too-cozy China ads have been used in the race for an open U.S. Senate seat in swing-state Pennsylvania.

Republican Dave McCormick ran a TV ad declaring: "We all know China created COVID. It's time to make them pay for it." 

We rated his claim False, as there is no evidence to establish that China created the virus.

Another GOP Senate contender in Pennsylvania, physician and TV host Dr. Mehmet Oz, ran a TV ad that attacked McCormick, the former chief executive of a hedge fund, as being too friendly with China. 

The hedge fund manages roughly $1.5 billion on behalf of Chinese investors, the New York Times reported. McCormick resigned his post in January 2022.

Oz has also run social media ads pledging to be tough on China.

The Pennsylvania race, which includes a contested Democratic primary as well, is considered a tossup. It’s one of the races that could determine which party controls the Senate, now split 50-50.

Also taking the get-tough approach is Alex Lasry, a Democrat who is running in a contested primary for the seat held by Sen. Ron Johnson, R-Wis. Lasry, a Milwaukee Bucks basketball team executive, pledged in a TV ad to "finally stand up to China."

Wisconsin political strategist Patrick Guarasci, who has worked with Democrats, said the Republicans’ China ads are influenced by former President Donald Trump. He cited what he called Trump’s "attempts to deflect blame for his mishandling of COVID-19" as well as his trade war with China. 

"These voters have heard him blame China for his own failings, and I think the candidates running in these GOP primaries are trying to run with that," Guarasci said.

The Trump influence is seen in North Carolina, where GOP Rep. Patrick McHenry is seeking re-election. 

McHenry has run several ads on Facebook and Instagram that mention China, including one ad on Facebook and Instagram that describes McHenry as "Trump Tough on China." 

Too-cozy with China attack ads have run several states including Texas. On March 1, Texas became the first state to hold its midterm primary election.

Don Huffines, one of the Republicans who challenged GOP Texas Gov. Greg Abbott, declared in an ad on Facebook and Instagram: "Under Greg Abbott’s leadership, Texas is putting taxpayer dollars into Chinese companies." We rated the claim Mostly False. The governor is not directly investing Texas tax dollars in Chinese companies. Huffines’ attack alluded to investments made by Texas’ public pension systems. Abbott won the primary on March 1. 

The ad linked to a San Antonio Express-News story from a day earlier that carried this headline: "Texas invests over $9 billion in China despite ‘hostile nation’ rhetoric from GOP leaders." Abbott did not respond to a request for comment, according to the story.

In Missouri, a super PAC backing Republican former Gov. Eric Greitens attacked Republican Attorney General Eric Schmitt with a TV ad over Missouri legislation Schmitt supported that helped China, in a claim we rated Half True. The Missouri seat is judged by campaign watchers as "solid" Republican.

Dennis Goldford, a political science professor at Drake University in Iowa, said that China, "both as a rising power in the world and as such a ubiquitous presence in so many aspects of the American economy, becomes an easy target that resonates with people fearful of the way the country and the world are changing."

"Voter intensity and turnout always matter, but they matter their highest in midterms, when we tend to find fewer casual voters, and emphasizing threats to the American way of life if the other side wins is a means of driving up intensity and turnout," he said.

Attacks on Republicans have been made in Ohio, Nevada and Wisconsin, as well.

In Ohio, a super PAC supporting Republican Josh Mandel claimed in a TV ad that former state GOP chair Jane Timken’s family business moved jobs to China. The Timken family steel business was not a part of her family of origin but belonged to her husband’s family.

In Nevada, where Republicans are vying to take on Democratic U.S. Rep. Susie Lee, GOP construction company owner John Kovacs used an ad on Facebook and Instagram to attack GOP attorney April Becker. 

It showed a snippet of a selfie video in which Becker said, "Happy Chinese New Year, everybody!" and claimed that Becker  "apparently is unaware of the growing tensions" over issues such as China’s human rights abuses. (The selfie video was taken during Las Vegas’ Lunar New Year parade, according to her Instagram account.) Becker called for a U.S. boycott of the 2022 Winter Olympics in Beijing, citing the disappearance of a Chinese tennis star who had accused a Chinese official of sexual assault.

The race is in the 3rd District, which covers an area southwest of Las Vegas, where campaign watchers expect voters to lean Democratic and the seat to be "likely Democratic."

And in Wisconsin, the Democratic Senatorial Campaign Committee ran a TV ad making a variety of attacks on Johnson, including a claim that he has been "rewarding companies that outsource to China," an apparent reference to fears that Trump’s 2017 tax law, which Johnson supported, would encourage moving jobs overseas.

We rated that claim False. Experts said there is no clear evidence that the law, which has no provision specifically for China, led U.S. companies to move jobs to China.

Polls may give some indication about why ads have focused on China. 

Fully 76% of people in the United States have an unfavorable view of China, according to a June 2021 report by the Pew Research Center. A March 2021 Gallup poll found that 45% of Americans said China is the greatest enemy of the U.S., more than double the percentage who said so in 2020. In just one year, China supplanted Russia as the country Americans believe to pose the biggest threat, according to that poll. 

Democrats have been targeted as well.

President Joe Biden was attacked in three Facebook ads that claimed his Build Back Better bill would enrich China financially through trade. The ads were run by Stand Up To China, a Tampa, Fla.-based group. It did not respond to a phone message we left.

We rated False the group’s claim that Build Back Better "would be a huge payday for Chinese manufacturing" and "would fill our streets with cars made with Chinese parts." Experts said there is no evidence that the domestic-focused legislation would be a financial boon to Chinese companies.

David Dollar, an expert on China’s economy at the Brookings Institution, said, "None of the financing in the Build Back Better Act that passed the House goes to China. It is targeted to pre-K education, childcare, health care, housing and clean energy."  

Derek Scissors, an expert on the Chinese economy at the American Enterprise Institute, said, "There’s a legitimate general concern that moving toward greener energy can benefit China, because China has spent a lot of effort and money to try to dominate global production of a variety of green energy equipment."

But Scissors said the legislation could easily be written so that companies that accept federal funds to pursue green energy initiatives would be required to buy products made in America or in countries friendly to America.

House Speaker Nancy Pelosi was targeted in a Facebook ad by Rep. Young Kim, R-Calif. The ad claimed that a House-passed bill touted by Pelosi that aims to make the United States more competitive with China "plays right into Xi Jinping's hands," referring to China’s president.

Democrats said the bill would increase U.S. semiconductor manufacturing, while Republicans said it did not do enough to counter China.

"Criticisms of the Chinese government from both Democrats and Republicans are a perennial feature of campaign ads and rhetoric over the past 20 years or so," said Zachary Peskowitz, a political science professor at Emory University in Atlanta. 

"These ads are likely to be effective among primary voters who are concerned about China's rise as a leading world power or worked in industries that are exposed to Chinese import competition."

RELATED: Republicans facing off in 2022 GOP primaries are running ads claiming the 2020 election was stolen