A collective groan could be heard on Monday when Philadelphia said it was reinstating the city’s mask mandate. It was a bad omen for Democrats. Leave aside whether it is necessary — most experts, including the Centers for Disease Control and Prevention, think it is not — liberals will pay a price for any restrictions, even essential ones. Voters were already furious about the school closures in the first year or more of the pandemic that in hindsight look like overkill. A return to enforced masking is just the kind of move that will boomerang. The question is whether Democrats can reverse their waning fortunes. The party was already facing probable defeat in this November’s midterm elections. Recent trends threaten to turn that into a wipeout. Pollsters pay close attention to the enthusiasm gap — the difference in motivation between Republican and Democratic voters. That was already at 11 percentage points in November last year when Democrats lost the governor’s race in Virginia. Since then it has widened to a yawning 17 per cent. Most of the factors that fed into the Democratic defeat in liberal-leaning Virginia have deteriorated since then. These include inflation, which hit 8.5 per cent last month, its highest rate since December 1981; friction over lingering pandemic restrictions, which most Americans believe should be over; illegal immigration, which looks set to rise next month after President Joe Biden scraps the Title 42 rule that allowed border guards to turn people away on pandemic grounds; and anti-incumbency. Biden’s approval rating has continued to fall. At 41 per cent, it is only a point or two higher than Donald Trump before the 2018 midterm landslide against Republicans.