

The Democrats are not Left wing. They’re left of the Republicans, and less authoritarian, but they’re a right-wing party who crippled banking regulation in favor of oligarchy, bailed out the worst banks, lied about drilling for oil[1] and causing a mass extinction event, and kept giving Israel weapons even after they went from defending themselves to committing genocide.
The goal for ethical people is not to get the Democrats to win, but instead to elect ethical people to government, e.g Hawkins and Nader.
It’s possible, even in FPTP voting systems, for people to reject the 2 parties that usually wins - see the UK where the Tories or Labour have been the only 2 winning parties for more than 90 years (including 2 short coalition governments); but where polling shows the 5th party (the horrible Reform) and 8th party (Greens) are now leading.
“It is infinitely better to vote for freedom and fail than to vote for slavery and succeed.” - Eugene V. Debs, Appeal to Reason, 1900-10-13
“Wage-labor is but a name; wage-slavery is the fact.” - Eugene V. Debs, The Socialist Party and the Working Class 1904-09-01
[1] https://www.washingtonpost.com/climate-environment/2024/08/16/biden-oil-drilling-production/ As he campaigned for president in 2020, Joe Biden made a bold promise at a New Hampshire town hall, adding repetition for emphasis: “No more drilling on federal lands. Period. Period. Period. Period.” […] The Biden administration has now outpaced the Trump administration in approving permits for drilling on public lands, and the United States is producing more oil than any country ever has.


From your point-of-view, the Democrats winning is good, and the Republicans winning is bad. You might see them on a left-right scale of 0-10, where 0 is good, the Ds are at 3, the Rs at 9, and Hitler at 10.
Some other people see a bigger window than that: look at https://www.politicalcompass.org/uselection2020 and compare how these people see the distance between Trump +9+9 and Biden +7+6, compared to the distance between both and Hawkins -5-3. These people agree that the Rs are worse than the Ds, but they don’t want to help the Ds win because the Ds are mass-extinction causing capitalists. To convince these people to vote for the Ds instead of Greens/socialists/not-voting at all, you have to convince them that the Ds actions of:
are good, and worth voting for.