Boomers deliver surprise strength for Biden

• The biggest trend at risk is the notion that voters become more conservative as they get older, Politico's Steven Shepard writes in a deep dive on the polling.
• While baby boomers appear to be holding firm on their liberal leanings, Gen Z is showing a surprisingly strong conservative bent.

The big picture: The comparatively liberal boomers are aging into the senior vote as their more conservative older siblings in the Silent and Greatest Generations die off.

• There were zero senior (65+) boomers in 2008.
• Boomers now represent 70% of the senior vote, the N.Y. Times' Nate Cohn notes.

Between the lines: Polls are a snapshot in time, and it's harder to poll than ever thanks to cellphones, spam blockers and voters who are more resistant to being polled.

Zoom in: The youth vote is giving pollsters the most fits right now.

• To spice it up, youth voters are showing signs of making former President Trump the first Republican to win that demo since George H.W. Bush in 1988.

• Polling for young Hispanic voters is "all over the place," John Della Volpe of the Harvard Kennedy School Institute of Politics told Politico.
• Polling for young Black voters is also breaking the trend line, with Biden suffering major losses of young Black voter support, Don Levy of the Siena Poll told Politico.

The bottom line: If these two long-term trends fall, there's another that seems less likely to change this time around.

• Old people vote at high rates. Younger ones don't.