Democratic Senate candidates in battleground states are betting big that the minimum wage will save their party’s majority. The issue may be the best hope they have to boost Democratic turnout.

With polls indicating the Republican Party may retake the Senate in the November midterm elections, candidates such as Alison Lundergan Grimes in Kentucky and Michelle Nunn in Georgia pushed an increase in the minimum wage especially hard over the Labor Day weekend, since it is among the few issues where they hold a clear advantage.

The Democrats' push builds on earlier efforts by liberal activists to raise the issue in battleground states, in effect priming the pump for the fall elections.

In addition to Senate Democrats introducing a bill to raise the federal minimum to $10.10, bills increasing the statewide minimum were introduced in the state legislatures in battleground states Alaska, Georgia, Iowa, Kentucky, Louisiana, New Hampshire, North Carolina and Michigan.

Only Michigan passed an increase, making it still a live issue in other states. In addition, ballot initiatives will ask voters to approve statewide increases in Alaska and Arkansas.

A wage increase has not been promoted simply to help Democrats — activists favor an increase for its own sake — but it didn't hurt that it could serve as an electoral wedge issue.

Labor groups have staged rallies throughout the year, often calling for a $15 minimum wage. Democrats have jumped on the theme.

"The phenomenon I am seeing is that candidates are choosing to make it the focus of their campaigns. I think you are seeing that in Iowa and in Kentucky [especially]. It is a very good issue to draw a contrast in the race between the Republican and the Democrat," said Arun Ivatury, campaign strategist with the National Employment Law Project Action Fund, which advocates for a higher minimum.

At a Louisville event, Grimes slammed opponent Senate Majority Leader Mitch McConnell, saying he would "not even consider" a vote on "actually raising the minimum wage."

Nunn, Georgia's Democratic Senate nominee, similarly touted a wage hike at an Atlanta rally, saying it would be "good for Georgia, and I think it'll be good for the United States."

President Obama echoed the theme at a Milwaukee event and made it the subject of his weekly radio address.

"The bottom line is, America deserves a raise. But until we've got a Congress that cares about raising working folks' wages, it’s up to the rest of us to make it happen," the president said.

Republicans view it differently. Democrats tried to make hay out of a secretly recorded tape released last week of McConnell complaining about Senate Democrats scheduling votes on raising the minimum wage. But it required them to highlight his reason: A raise would "cost the country 500,000 new jobs."

McConnell was referring to a February study by the nonpartisan Congressional Budget Office that said raising the minimum wage to $10.10 by 2016 would lead to a loss of about 500,000 jobs. The study has often been cited by GOP lawmakers, and conservative activists argue the report took much of the issue's momentum away.

Polls generally show broad approval for raising the wage. A June CNN telephone poll found that 71 percent of Americans favored a generic increase in the minimum wage.

Perhaps more importantly, the poll found approval hit 90 percent among Democrats, suggesting the issue particularly excites the party’s base.

Off-year elections are notorious for having major drop-offs in the size of the electorate, and historically a two-term president’s party takes the bigger hit. So Democrats need to find ways to excite their party’s core voters.

But the the minimum wage isn't a hot-button issue among voters. The CNN poll showed that overall approval for raising the wage slid to 52 percent when it specifically asked about the proposed $10.10 wage. Even support among Democrats fell to 72 percent. That suggests that while support is broad, it isn't deep.

A Kentucky robopoll by Survey USA in late August had similar results, with 55 percent of registered voters overall and 71 percent of Democrats favoring an increase in the minimum wage to $10.10. The same poll found that McConnell leads Grimes 46-42 percent, though that was within the poll's 4.2-point margin of error.

"Maybe with those core Democratic voters it does something," said Josh Withrow, legislative affairs director for the conservative activist group FreedomWorks. "But I fail to see it having much impact on the general electorate."

But reaching all voters is not necessarily the point. Democrats just need to give their people a reason to head to the voting both.