DULUTH (AP) — Minnesota Democrats face a major challenge as they seek to keep Gov. Mark Dayton and U.S. Sen. Al Franken in office: getting their supporters to show up at the polls.

Meanwhile, Republicans are encountering a different kind of obstacle: uniting their party after a fractured state convention and a potentially divisive primary campaign ahead.

Dayton and Franken had no opponents for the Democratic-Farmer-Labor endorsement when the party’s state convention convened Saturday in Duluth, so they have the luxury of being able to focus on turning out their voters.

But the GOP convention in Rochester took 10 ballots to endorse investment banker Mike McFadden for U.S. Senate and four to back Hennepin County Commissioner Jeff Johnson for governor. McFadden’s win spares him a hard primary fight, but Johnson will face former state Rep. Marty Seifert, businessman Scott Honour and former House Speaker Kurt Zellers in the Aug. 12 primary.

DFLers may be united behind their candidates, but their leaders stressed the need to translate that unity into persuading voters who supported Democrats in 2012 to turn out in an off-year election that’s already expected to be tough for the party nationwide. Another challenge will be preventing defections to the GOP over proposals for copper-nickel mining, which have strong support in the Democratic stronghold of northeastern Minnesota but face opposition from environmentalists and urban liberals.

U.S. Rep. Keith Ellison laid out the turnout challenge in stark terms, saying Democrats have a “massive job” ahead.

Ellison reminded delegates that in the 2010 off-year election, Republicans took control of both the state House and Senate and defeated an incumbent congressman. But he pointed out that the DFL regained control of the Legislature, took the governor’s office and defeated constitutional amendments that would have banned gay marriage and required voters to show IDs at the polls when Democratic turnout surged in 2012.

“It’s going to take shoe leather, it’s going to take hard work, it’s going to take getting out the vote, and we’ve got to always be expanding,” Ellison said. “And that means when you leave this convention room … you’ve got to go out, back to your community, ready to fight, ready to knock on doors, ready to make calls.”

A competitive U.S. Senate race will ripple up and down the Minnesota ballot, and a Franken loss could help tip control of the Senate to the GOP. Minnesota Republicans say they’re seeing early signs of national help in the form of “boots on the ground” — field staffers and shared campaign office space. McFadden’s ability to avoid a tough primary will make those resources multiply, predicted Chris Tiedeman, a Minnesotan on the Republican National Committee.

“The resources that help at the United States Senate level are going to help our legislative candidates, they’re going to help our constitutional candidates. It’s going to affect voter turnout,” Tiedeman said.

State GOP Chairman Keith Downey said 10 field staffers are mobilizing across Minnesota this week to coordinate volunteer efforts. He said more field staffers could be added as the campaign season wears on.

Bound for the Minnesota GOP’s first competitive statewide primary in 20 years, Johnson said he thinks his being endorsed for governor still carries considerable currency with Republicans. And he said he has experience in transcending partisan divisions.

“We are really good at winning over people’s minds. We have facts and logic behind us,” Johnson said after winning the endorsement Saturday night. “Sometimes we are not as good at winning over their hearts and that is what we are going to do.”