As long as Republican politicians and voters keep on boxing themselves in on vaccine mandates, they will continue to provide opportunities for Democrats from California to Georgia.

It goes without saying that last August was the most testing period of Joe Biden’s presidency. Coming into August, Biden consistently had positive net approval ratings of around 10% throughout his tenure. But during the fall of the Afghan government and the spread of the Delta variant, his approval ratings took a massive hit, falling rapidly into the negatives for the first time of his presidency. It was one of the most rapid changes in political sentiment, in any direction, in many years.

This makes the coming months crucial for the future of the Democratic Party, as they are the last period for public opinion to shift before the 2022 campaign season begins in earnest. Biden and his administration seem to have recognized this, and they began the month of September by making a major, decisive shift on a policy issue they had previously refused to touch: vaccinations. For the first time, the administration enacted a vaccine mandate, instituting new rules that some estimates expect that this could affect up to 100 million Americans.

This decision has confused many across the political spectrum. For months, the administration had taken a unifying, non-combative approach towards the vaccination issue, focusing on assisting production and distribution during their first months in office. After vaccines became widely available, they took a passive, PR-focused stance in the months after out of fear of alienating the unvaccinated.

Even as vaccination rates slowed and cases surged, the administration still shied away from taking action. Why would the administration go out of their way to make such a controversial move, especially after an August that was so politically brutal?

The answer is surprisingly simple: vaccination mandates, while controversial, are not at all unpopular. Polling conducted in the five states that went for Trump in 2016 then Biden in 2020, including Georgia, showed 60% or more approval for a similar policy consistently. Such a consensus is incredibly rare for an issue of such high importance.

The administration knew this. Instituting the new mandates was not a panicked move made by an out of touch administration. It was a carefully considered political maneuver with significant public support.

Even beyond the immediate popularity of the move, it also has another potent political effect: forcing Republicans on the wrong side of the vaccination issue. Immediately after Biden announced these new rules, Republican elected officials, like Georgia’s own governor Brian Kemp, announced their virulent opposition to them despite polling showing how popular Biden’s stance is.

This did not happen because these politicians are unaware that their new positions on vaccines are unpopular. They took these stances because they knew that was what the puritanical Republican base wanted. In other words, Biden caught them in a political trap.

And unlike most new political strategies, this tactic now has a proof of concept. While most of America was focused on the Delta variant, school reopenings and the Taliban takeover, Governor Gavin Newsom of California was in the middle of a recall campaign, fighting to keep his position in his state. While the outcome of such an election might seem to be a foregone conclusion in such a liberal state, some polling suggested that Newsom was in danger.

What did Newsom do? Like Biden is doing now, he leaned heavily into vaccine mandates, casting Republicans as a dangerous party that cared more about the feelings of radical extremists than public health. Like clockwork, this enraged the Republican base, boosting their support of paleoconservative radio host Larry Elder, who had a long track record of offensive and unpopular statements and positions.

With a toxic opponent, Newsom then casted the election as a binary choice between him and Elder. This further motivated the Democratic base and got independents back on his side. Support for the recall effort collapsed almost overnight.

By the end, the once-competitive election ended up being a blowout, a crushing margin even bigger than Newsom’s initial victory in 2018. Beyond the margin itself, Newsom also showed outright growth in traditionally conservative counties that trended left under Trump, winning places like Orange County, also by larger margins than in 2018. He kept Black turnout high, prevented defections from urban liberals and even reversed many of the gains Trump made in 2020 among minorities.

Newsom did not just survive: he made gains, even relative to the strongest year for Democrats in decades. The governor achieved a complete victory, the kind of result one would expect to see in a strong midterm for Democrats.

Of course, not every state is like California, and Newsom had many unique advantages, the most notable being California’s extensive mail voting program. But the result is the same: by trapping Republicans into unpopular positions and attacking those positions relentlessly, Newsom was able to engineer a swift political comeback.

It’s no surprise that Biden is attempting the same strategy on the national scale. And as long as Republican politicians and voters keep on boxing themselves in, they will continue to provide opportunities for Democrats from California to Georgia.