Curtin notes that while the gap between Democrats and Republicans has widened, their trend lines almost always move in the same direction. Independents tend to track closely with the overall average. And party affiliation is just one of many demographic gaps in consumer sentiment: Young people tend to be more optimistic than older people, and richer people more upbeat than poorer, for example.

Still, an increasing number of real-world studies has found that partisanship does in fact drive consumer behavior.

Shopping Searches
Microsoft economist David Rothschild looked at online shopping searches for big-ticket items in the year before and after Trump’s election. What he found was little change in Republicans shopping for cars and houses — but a drop-off by Democrats.

Stanford University economists conducted a number of real-world experiments to test whether partisanship shapes buying and selling decisions.

In one, workers bidding for freelance assignments in an online task marketplace would quote lower prices if they knew they’d be working with someone who shares their political views. In another, people were less likely to purchase reduced-price Amazon gift cards from someone whose politics they disagreed with.

“Taken together, this amounts to compelling evidence that partisan sentiment affects economic behavior in contemporary American society,” economist Christopher McConnell and his co-authors concluded.

All those studies are important because they measure how people actually behave rather than what they tell survey-takers.

That behavior may not be irrational. Democrats really could be worse off than Republicans under the Trump presidency.

The 2018 tax overhaul, for example, capped deductions for state and local taxes at $10,000 — regardless of filing status. That disproportionately affected taxpayers in Democratic states that tended to have higher home prices and higher taxes. And Trump’s military spending, farm subsidies and energy policies have disproportionately helped states that vote Republican.

“I think the Democrats would be very cautious. We’re in such uncharted territory coming out of this Covid recession,” Rothschild said.