A commissioner's meeting that turned ugly in Florida's Palm Beach on Tuesday, after the city authorities made it compulsory to wear a mask indoors, offered a glimpse at just one of a complex set of reasons that is driving up coronavirus cases across the US.

"Masks are literally killing people," one angry citizen told the city officials.

She is wrong; study after study has proven that wearing masks is a key factor in curbing the spread of the coronavirus.

Yet scepticism about masks remains, and the very act of wearing one in parts of the United States has become ideologically charged even as some states rushed to restart their economies too soon, said experts.

With some exceptions, such as California and Washington, it has been Republican states led by Florida, Texas and Arizona which have seen virus cases rise the most this month.

They include Oklahoma, where many in the 6,000-strong crowd who turned up at a campaign rally by President Donald Trump in Tulsa last Saturday did not wear masks.

Many states ignored Centres for Disease Control and Prevention guidelines and, under pressure, reopened parts of their economies in the last week of May. This has led, a month later, to the current surge in cases, and the health authorities and hospitals are now bracing themselves for a wave of deaths to follow.

The pandemic initially hit Democrat-ruled states such as New York and California hardest, where mayors and governors moved aggressively to curb the coronavirus.

In the early days, people were told that wearing masks was not necessary - advice designed to prevent a run on masks, which were in short supply for front-line health workers who needed them most. But as the economy cratered and Mr Trump, who is seeking re-election in November, saw that critical aspect of his incumbency advantage vanish, pressure grew for states to reopen their economies, and any resistance from worried state leaders was painted in political terms.

"President Trump's orientation towards optimism and cheerleading led him to consistently downplay the crisis; add to that an election cycle and coronavirus response became maximally politicised," Dr Ian Bremmer, founder and president of Eurasia Group, wrote in an e-mail.

Wearing a mask in public became an emblem of the ideological divide as Mr Trump and senior advisers emphasised personal choice and did not themselves wear masks in public. Supporters very clearly took their cue from the President; some at events have even called journalists wearing masks "communists".

On Tuesday, as Dr Anthony Fauci, the administration's top infectious disease expert, warned lawmakers of the need to continue strong measures in the face of a "disturbing surge" in coronavirus cases, Mr Trump told an audience at a mega-church in hot spot Arizona - almost none of whom wore masks - that the virus was "going away".

It was a direct contradiction of Dr Fauci's advice; he had told Congress in no uncertain terms: "The virus is not going to disappear".

Another reason for the surge, wrote Dr Bremmer, is "a more focused orientation towards personal liberty (and) mistrusting authority in the United States which is reflected in different preferences on free speech, gun ownership... and avoiding lockdown".

This emphasis on personal freedoms - a reflection in part of lack of trust in government - has merged with science scepticism of the kind motivating the citizen who spoke out angrily at the Palm Beach meeting.

Said Dr Fauci on June 18: "One of the problems we face in the United States is that unfortunately, there is... an anti-science bias...

"People, for reasons sometimes… inconceivable and not understandable... just don't believe science and they don't believe authority."

He added: "That's unfortunate because, you know, science is truth...

"It's the same thing that gets people who are anti-vaxxers, who don't want people to get vaccinated, even though the data clearly indicates the safety of vaccines. That's really a problem."