> There's evidence to suggest voters preferences don't really impact policy in the long term, such as the Princeton study.

The dirty little (open) secret of US politics: nothing, nothing an individual does really matters unless they put in tons of time (time doing things, not reading Twitter), tons of money, or both. And even then it's a crapshoot unless you've got serious cash.

Less true at a very local level. Definitely true of anything past the county level or so.