“suppression of votes” - Why would a GOPer say that?
Probably because they don't know all the code words, one of those code words being "suppression" which usually connotes an illegal activity.
the attacks on the Clintons are also aimed at the "suppression of votes" from millennial women, African-Americans and the "idealistic Bernie Sanders supporter.""Principally, we're trying to drive them to a third party or just have them not vote," the source said.
He could have skipped the phrase altogether, and made the point. Non-issue negatives against the opponent are generically designed to drive people to other candidates, or to stay home.