British lawmakers will vote Tuesday on whether to approve new restrictions to curb the spread of the omicron variant — and many will have more than public health on their minds when they say yes or no.

The votes are also an opportunity to express unhappiness with embattled Prime Minister Boris Johnson, whose approval ratings — both with voters and inside his own Conservative Party — have plunged amid ethics scandals and allegations the government breached its own pandemic restrictions.

The House of Commons is voting on measures that take effect this week, ordering masks to be worn indoors in England, changing rules on self-isolation and — contentiously — requiring proof of vaccination or a negative coronavirus test to enter nightclubs and large crowded events.

Vaccine passes have become commonplace in many European countries, but Johnson’s government has resisted introducing them in England, although the governments of Scotland, Wales and Northern Ireland, which set their own health rules, have done so.

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The British government argues that the highly transmissible omicron strain has changed the argument, and vaccine passes are now a sensible measure.

“Omicron is a grave threat,” Health Secretary Sajid Javid told lawmakers. “Scientists have never seen a COVID-19 variant that is capable of spreading so rapidly. So we have to look at what we can do to slow omicron’s advance.”

Many Conservative legislators, however, argue that vaccine passports are economically damaging and a restriction on individual freedoms. One right-wing lawmaker, Marcus Fysh, went so far as to compare the plan to Nazi Germany.

Deputy Prime Minister Dominic Raab called that comparison “crass.”

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Raab said the virus restrictions “are a proportionate, targeted approach, given what we don’t know and the precautionary approach we need to take, just temporarily, while we get to grips with omicron.”

Others argue that the vaccine pass proposal will do little to stop the spread of the virus. Conservative legislator Tobias Ellwood said the plan was “illogical” because the emergence of the more vaccine-resistant omicron variant means double vaccination is no longer a firm guarantee against infection.

Dozens of Conservatives could rebel against the government on Tuesday, though the measures are still highly likely to pass because the opposition Labour Party supports them.

The vote is a sign of growing discontent in Conservative ranks with Johnson. The party picked him to be leader in 2019 because he promised to “get Brexit done” after three years of gridlock over Britain’s departure from the European Union under Prime Minister Theresa May. The same promise helped Johnson win a December 2019 election with an 80-seat majority in the House of Commons, the biggest for any Conservative leader since Margaret Thatcher in the 1980s.

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Since then the pandemic and a series of scandals have chipped away at the support for Johnson and his government. Johnson’s initial reluctance to impose a nationwide lockdown in early 2020 helped give the U.K. the highest coronavirus death toll in Europe apart from Russia, with more than 146,000 deaths.

A successful vaccination program helped Johnson recover some of his authority, but his government has faced damaging allegations that it flouted the coronavirus rules it imposed on everyone else with reports that Johnson’s 10 Downing St. office held lockdown-breaching Christmas parties last year. Johnson has ordered an inquiry, but insists he personally broke no rules.

The government also faced charges of cronyism when it tried to block the suspension of a Conservative lawmaker found to have broken lobbying rules by advocating on behalf of two companies who were paying him. The government changed tack after an outcry and the lawmaker, Owen Paterson, resigned.

A special election on Thursday to replace Paterson could add to Johnson’s woes. Polls suggest the opposition Liberal Democrats may take the seat from the Conservatives. Nationally, the opposition Labour Party has opened up a strong lead in opinion polls.

Since a national election is not scheduled until 2024, the danger for Johnson comes largely from his own party. The Conservatives have a long history of dumping leaders when they become unpopular.

“Clearly, he is in trouble,” said Tim Bale, professor of politics at Queen Mary University of London. “The question is whether that trouble is terminal or not.

“I doubt whether he is in any immediate danger — he will still be there by Christmas. But I think the new year will be an interesting few months.”