Republican voters have so far cast more early ballots than Democrats in three of the key swing states, giving the party a potential ray of optimism with less than two weeks before Election Day.
More registered Republicans have voted in Arizona, Nevada and North Carolina than Democrats, according to publicly available state data. The party affiliation doesn't mean that voters have to vote for their party's candidate.
I think that last bit is especially important to note: "The party affiliation doesn't mean that voters have to vote for their party's candidate."