User blog comment:Tr0llis/Voting System/@comment-4621372-20131203204003/@comment-32656-20131208155019

Yeah, most people have not heard of it because it has not been used much, or in a while. The parties quit nominating obvious criminals, is the jist of it. Suspect that we will see more of it in the near future, however, if the crazies take control over a chamber.

Essentially, they just vote to refuse them admission - refuse to let them join the chamber as a member. Alternatively, with the presidency, they could just refuse to ratify the Electoral College and have the same effect.

Prominent examples would be from Reconstruction, and the few years after that. Several blacks were refused admission under the rule. Believe that it has been used since once or twice for criminals. Still on the books though.

Now, that rule is for after an election, but before admission. They can also be expelled after admission.

As for prior to an election, you have the primaries. Much the same effect, really. Other countries have this in more a form like a simple ballot at the local party meeting.