Nearly half of Minnesota voters gave last month's election a pass.

Fewer than 2 million people — 50.51 percent of the voting population — cast ballots in November. That's the lowest turnout the generally high voting state has seen for nearly three decades.

Minnesotans had lots of company in staying home on the first Tuesday of November. A national study, from University of Florida's Michael McDonald, found that the 2014 election was the lowest turnout contest since World War II.

While many states have long had basement-level turnout, Minnesota had proudly boosted of being among the top voting states in every election. For at least a decade, its voters have turned out in greater numbers than all but one or two other states.

No more.

Alaska, Colorado, Maine, Oregon and yes, Wisconsin, all beat Minnesota's turnout, according to McDonald, with the Gopher State ranking sixth in the country.

Why Minnesota's turnout was so law is particularly baffling in a year when voting was easier than it's ever been. More voters preregistered than in many other years and more Minnesotans used absentee balloting, taking advantage of the new 'no excuse' absentee ballot law.

"It's a million-dollar question," said Ken Martin, the DFL Party chair. He plans to crunch voting data in the coming months to look for explanations.

"Voters just seem to be more apathetic and it plays out, especially in the midterms," said Keith Downey, the Minnesota Republican Party chair.

Among the early theories:

The 'meh' top-of-ticket theory: Gov. Mark Dayton and U.S. Sen. Al Franken, both Democrats, led their opponents the entire election season, which did little to create the sense of urgency that sends voters to the polls. Their respective Republican opponents, Hennepin County Commissioner Jeff Johnson and businessman Mike McFadden, failed to spark enough excitement among the electorate to change the outcome.

The grossed-out electorate theory: "There is a real deep seated cynicism about government and politics, especially among young people," said DFL Rep. Steve Simon, the newly elected secretary of state. He's talked about technical changes to encourage voting, including the ability to vote early and preregistration for 16- and 17-year-olds, but admits those may not increase turnout. "If they are not inclined to vote, no technical fixes in the world will coax someone who is thoroughly disgusted to vote," he said.

The late barrage theory: Martin said campaigns tend to pour on the cash close to Election Day, on the theory that undecided voters make up their minds late. But, since a lot of that cash goes to negative ads, it may have the opposite effect. Martin said his hunch is that "it is actually probably suppressing the vote rather than raising turnout."

In some ways, the low turnout worked out well for both sides. Democrats won every statewide race and maintained their dominance of the state's U.S. House delegation. Republicans managed to wrest control of the Minnesota House from DFLers, putting them back in the game at the Capitol. But Minnesota partisans will continue to dig deep to figure out how to get the state's normally enthusiastic voters to get excited again.