Here's what you need to know about today's Nevada presidential primary

"I Voted" stickers at a polling station at Thunderbird Family Sports Complex in Las Vegas on Feb. 6. The state is host to dueling contests this week, a state-run primary on Tuesday that holds largely symbolic significance and a party-run caucus two days later when delegates will be allocated. (Bloomberg via Getty Images)

Democratic and Republican voters in Nevada head to the polls today for the "first-in-the-West" primary election.

Nevada is one of six swing states that will get outsized attention in the general election and is the first swing state to vote early, making it a testing ground for the candidates, even if the races aren't that competitive on paper.