Not to say that everyone that votes for Trump is a Nazi, but we do know who the Nazis are voting for.
When you register to vote here, you can have a party affiliation and can give them permission to contact you.
Sorry was implying they you provide the information. Also when you move you update your voter registration.
The dialer software connects to a database with a huge set of phone numbers organized in various ways. The calls are often narrowly targeted - sometimes you are calling to confirm attendance at an event, sometimes you are leaving a scripted message for numbers that are known to always go to voice mail. You don’t do any literal dialing, you press a “next call” button and wait for someone to answer.