you could also vote for a different president candidate, like “none of the above” while voting for a local candidate you do like.
Why would that mean anything?
There are really only three choices. Democrat, Republican, and “I don’t care you guys pick”.
It’s doesn’t mean anything because that’s what everyone thinks the choices are.
If someone other than D or R started to get some serious traction, you could see a snowball over 8-12 years.
I’m gonna piggyback on this to make a related point:
If you take it down from +15 points to +14 points, that’s gonna cost the GOP more money next time around. You don’t have to win your state to make an impact. If you can make it more expensive to win your state, that takes funds away from their campaigns in other states.
(And if you make it cheaper for Democrats to win your state, that frees up funds for campaigns in other states.)