Are Polls Understating Support for Republicans?

Over the last three months, political journalists have been reporting a trend toward Democrats. The Supreme Court’s reversal of Roe v. Wade, they have reported, has provided increased motivation for Democrats to turn out and vote. The easing of gas prices from their springtime peak has reduced concern about out-of-control inflation. Biden administration legislative victories have raised Democrats’ morale.
These are plausible points, validated by polling showing Republicans’ 3–4 percentage point advantage in the generic vote for the House collapsed to a dead heat in …