VIRGINIA, USA — In 15 participating states and one U.S. territory, Super Tuesday is when the most states hold primaries and caucuses on the same day.
Other states and territories cast their votes on multiple dates between January and June.
So, why doesn't everyone head to the polls on Super Tuesday?
Dr. Leslie Caughell, a political science professor at Virginia Wesleyan University, said it comes down to federal law, which only mandates the general election be held on the Tuesday after the first Monday in November.
"States control individual elections," Caughell said. "And that gives states and localities a lot of freedom to determine when and how they'll implement elections."
Virginia law mandates primaries be held on the first Tuesday in March. North Carolina law states the election take place on the Tuesday after the first Monday of the month.
While neither the Democratic nor the Republican national committees have direct control over the exact dates of primary elections, Caughell said their influence on the calendar is strong and strategic.
"Early primaries have a disproportionate amount of weight in terms of selecting who's the subsequent nominee," Caughell said. "I think there is also a sense in which it can be a little bit difficult, depending on what the primary schedule looks like, to campaign."
Still, Super Tuesday outcomes hold major implications for the presidential race.
With more than one-third of the total delegates available in both the Republican and Democratic primaries up for grabs. Caughell said frontrunners could come within striking distance of the nomination.
"This is one of those dates where if you don't perform by now," Caughell said, "it usually becomes a lot harder to fundraise, because nobody wants to spend money that's going nowhere."
Caughell said bills have been introduced multiple times in Congress to have one primary day nationwide, but those bills never passed.