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.
They could vote Libertarian, though. They are usually against war funding. In a two-party system, that’s technically a (half-)vote for Trump also, but at least they’d be making a point.
That point that the consequences anyone else experiences from Republicans winning are worth it to you to feel morally superior.