In the last few years, polling broke pretty badly. The timeline, as I see it, looks like this:
- In 2015 and 2016, the last years pollsters could reliably reach most voting demographics, there were polling errors in several states, but the national polls were mostly accurate. They showed that Hillary Clinton would win the popular vote, and she did.
- In 2017 and 2018, young people - who had previously been unreliable voters - started turning out in droves. Thanks to that, Democrats over-performed in virtually every special election and the midterms. Young voters are hard to poll, because they don't answer unknown callers on their cellphones, and don't have landlines.
- In 2019, the trend continued, with special elections landing firmly in the Democratic column.
- In 2020, Joe Biden won. Polls were wrong about both Democratic and Republican turnout, with both parties obliterating past records - but obviously, Biden pulled in more voters than Trump.
- In 2021, special elections that should have been cakewalks for Republicans flipped Democratic, beating polls by wide margins.
- In 2022, structural advantages that should have given the House and Senate both to the Republicans defied all expectations - and polls - to put the Democrats ahead in the Senate, and to give the Republicans such a slim majority in the House that it led directly to the clusterfuck there today.
- In 2023, once again Democrats over-performed substantially versus the polls. The Republican House majority slimmed further, and they lost multiple state legislatures.
Now, in 2024, the question is whether the pollsters have retooled enough to account for a youth vote that keeps confounding them. The youth aren't happy about Republicans overturning Roe v. Wade or a bunch of other decisions coming down from the conservative majority in the Supreme Court, but they're also not happy about the Biden administration's response (so far) to Israel's atrocities in Gaza. It's hard to imagine them actually flipping to Donald Trump, who would push for paving Gaza over entirely and loves authoritarians like Netanyahu, but it's easier to imagine them staying home if Biden doesn't put his foot down and deny Israel military assistance until Netanyahu is removed from power.
Regardless, I take all polling with a truckload of salt until the polls show they have resolved their issues and are starting to reflect reality again.