Tom Cotton told Fox News he did not believe virus originated in Wuhan market and said bioweapons link should not be ruled out

A Republican senator who floated a conspiracy theory which said the Chinese government created Covid-19 in a weapons lab claimed on Saturday that since he first learned of the outbreak, in mid-January, “common sense has been my guide”.

The Covid-19 outbreak began in the Chinese city of Wuhan, but has spread globally and by Saturday evening had killed more people in America, nearly 20,000, than in any other country. White House public health experts have said they currently expect a death toll of around 60,000 in the United States.

On Saturday, Tom Cotton of Arkansas, a foreign policy hardliner, wrote on Twitter: “Since I first learned of the Wuhan coronavirus in mid-January, common sense has been my guide.

“Not Chinese communist lies. Not ‘the models’. Not so-called ‘public-health experts’. Just common sense. Many elected leaders have also been guided by common sense. Others haven’t.”

The virus is believed to have originated in a market in Wuhan in which wild animals were sold. But in an appearance on Fox News in February, Cotton floated a conspiracy theory which suggests the virus was manufactured in a Chinese bioweapons facility.

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“Here’s what we do know,” he said. “The virus did not originate in the Wuhan animal market. Epidemiologists … have demonstrated that several of the original cases did not have any contact with that food market. That the virus went into that food market before it came out of that food market.

“So we don’t know where it originated. But we do know that we have to get to the bottom of that. We also know that just a few miles away from that food market is China’s only biosafety level four super-laboratory, that researches human infectious diseases.

“We don’t have evidence that this disease originated there but because of China’s duplicity and dishonesty from the beginning, we need to at least ask the question to see what the evidence says, and China right now is not giving evidence on that question at all.”

The Chinese ambassador to the US censured Cotton following his remarks on Fox and said the senator’s floating of the conspiracy theory was “absolutely crazy”. The senator walked back on the issue shortly afterwards and said the theory was one of “at least four hypotheses about the origin of the virus”.

But Cotton, other leading Trump allies and the president himself have continued to refer to Covid-19 as the Wuhan or Chinese virus, denying that it is racist or discriminatory to do so.

On Saturday, Texas senator Ted Cruz was among prominent figures to defend Bill Maher, after the comedian condemned protests against naming the virus with reference to China. Critics of Maher pointed out that Asian Americans have faced abuse and attacks since the virus took hold in the US.

More than 500,000 cases of Covid-19 have been confirmed in the US, with New York, New Jersey and Michigan worst hit. Together, the three states account for more than 10,000 deaths.

On Saturday, Cotton also took aim at Gretchen Whitmer, the Democratic governor of Michigan, regarding a stay-at-home order which deemed garden centers to be non-essential businesses.

“I get that Governor Whitmer is auditioning to be [vice-president],” Cotton wrote on Twitter. “Foolish, theatrical orders with no public-health benefits may generate headlines, but they undermine public confidence. Then again, Joe Biden called the China travel ban ‘xenophobic’. So maybe those two are a good match.”

In fact, though Trump placed restrictions on travel from China – which Biden now backs – he did not ban such travel entirely.

The World Health Organization has cautioned against travel restrictions, saying they can be counterproductive. Research indicates the virus mainly came to the US from Europe, not China.

Nonetheless, on Saturday Cotton also tweeted an opinion piece entitled: “Time to put China on lockdown for its dishonesty.”