The poll found 50% of Democrats approve of how Biden has navigated the conflict while 46% disapprove — and the two groups diverge substantially in their views of U.S. support for Israel. Biden’s support on the issue among Democrats is down slightly from August, as an AP-NORC poll conducted then found that 57% of Democrats approved of his handling of the conflict and 40% disapproved.
This assumes that everyone actually goes to vote.
If someone is disillusioned, they may sit out that vote. I know I’ve heard a few republicans basically say “I can’t vote for Trump, but I certainly can’t vote for a democrat, so I’ll just leave that one blank”. This could be a similar situation here, that folks disheartened by support given to a country going too far in a military response and unable to vote for it with a clear conscience.
Logically, one would realize the alternative is even worse and vote for lesser of evils, but some folks don’t vote that way.