November's midterm races could be affected by a surging youth vote, especially in a big Minnesota election year featuring a slew of hotly contested seats.

Minnesota is expected to be one of the states where the youngest voters could have the greatest impact, according to the Youth Electoral Significance Index, or YESI.

"We're hoping to see an overall increase in youth turnout, but are really looking to Minnesota to see a big jump," said Kei Kawashima-Ginsberg, director of Tisch College's CIRCLE at Tufts University, which produces YESI.

States and districts with high YESI scores tend to include some combination of significant youth populations (in this case, those aged 18 to 29), historically good voter turnout, high levels of education, lots of higher education institutions and systems that make registration and voting easy. While Minnesota's youth population isn't notably high, it ticks the other boxes pretty handily.

But if they're going to significantly influence 2018's results, younger voters will have to actually show up to the polls and reverse recent trends.

"The turnout has been really abysmal," said Kawashima-Ginsberg.

National youth voter turnout did increase slightly in 2016's presidential election with about 24 million casting ballots. But only about 20 percent of registered Americans aged 18 to 29 voted during 2014's midterm, the lowest rate ever recorded by the Census in the past few decades.

While Minnesota usually excels at voting, midterm participation has been sliding here too, and rough estimates show youth turnout in particular fell about 11 points between 2006 and 2014.

And campaigns seem to know that -- they usually spend their resources on targeting likely voters rather than others. About 70 percent of millennials surveyed by CIRCLE reported not being contacted by parties or campaigns before the 2016 election.

But that could be set to change, with 2017's youth voter turnout also rising in a number of special elections.

"Young people are realizing that midterms are just as important as presidential elections," Kawashima-Ginsberg said. "That's been a hard sell."

Gender, racial and LGBT equality, gun violence and other issues that America's youth care about have seen flashpoints in recent years, which has helped drive interest and engagement in the political process. And voting rights groups are reaching out to get them registered and involved.

"Young voters are new voters," said Carolyn DeWitt, president of Rock the Vote. "Because it's a new process for them, they need a lot more hand-holding."

She said Rock the Vote has been more focused on educating would-be youth voters on the process, and that they respond positively after better understanding how their vote affects policies. Social media has also helped young activists better connect with their peers on the issues.

It's possible that a youth voter surge would benefit Democrats more than Republicans since nearly 60 percent of millennials identify as Democrat or lean that way, according to the Pew Research Center. But a look at recent presidential voting trends suggests more diversity of political thought.

Nearly two-thirds of millennials nationwide voted for Barack Obama in 2012 overall, with young minorities skewing heavily Democratic. Donald Trump, however, won white youth over Hillary Clinton by five points.

Also, the number of millennials identifying as independents rose 8 points across the country since 2008, a sign of growing dissatisfaction with major political parties.

Geography also divides the youth vote as it does the general electorate, with cities skewing heavily Democratic, suburbs being more split and rural areas leaning Republican -- trends that may affect Minnesota's competitive congressional races should millennials turn out in higher numbers than usual.

Time will tell how much of a youth surge Minnesota and the nation will see this November. Races for competitive U.S. House seats, a special Senate election and a wide open gubernatorial contest all could be very close. And in close races, even slight boosts in youth voting could mean the difference between defeat and victory for candidates in either party.

"Leaders are elected to represent the points of view and the values of their constituents," DeWitt said. "If a young person wants to have a voice on an issue, they have to vote."