So there’s a risk if Biden is polling too well (I don’t think it will be an issue) people will stay home thinking they don’t need to compromise their morals because trump will lose.

That’s largely how Romney lost to Obama in 2012. Republican turnout sagged in a year when both candidates’ approval ratings were underwater. Mitt lost a bunch of midwestern states that a candidate like Bush or Trump could have won, thanks to his vulture capitalist career alienating blue-collar conservatives and his weird knock-off religion alienating evangelicals.