This interactive voting comparison comes courtesy of USARep.org, a site that helps you research voting records of members of Congress (both chambers). As the name implies, you can also compare voting records of two House members or two Senators, along with details of the bills or amendments voted on.
So, for instance, you can compare the 2020 Presidential Candidates, apples to apples, on their voting records. See below for a summary (scroll down to see House members) or go to http://usarep.org/presidentialPrimaries for more info.