It's not hard to see why union election efforts are so important.

It's not hard to see why union election efforts are so important.

Working-class voters—especially the white working-class voters so coveted by Mitt Romney's campaign—are a key swing constituency. Whether they turn out to vote, and if so, who they vote for, can determine the outcome of elections. Unions represent fewer people than they once did, but there were 14.8 million union members in the United States in 2011, and millions more union family members and retired members, people with whom unions have longstanding relationships. That can be a potent force, and unions are looking to put it to use in this election, to leverage it into a grassroots campaign that blunt some of the effect of hundreds of millions in Republican outside spending. From advertising against Mitt Romney to ads in targeted races on specific issues to the one-on-one field organizing at which labor excels, unions and allied groups are ramping up a giant election effort—one that can't match the dollars that will be spent by Karl Rove and the Koch brothers, but will aim to meet people where they live, face to face or through a focus on key issues.

Unions are mostly keeping their plans vague at this point, not wanting to give away too much just yet about where exactly they will be mobilizing volunteers, what races and what voters they'll be targeting. Of course, it's a fair bet that Rust Belt states like Ohio (especially Ohio), Michigan, and Pennsylvania will feature heavily in their plans. Massachusetts will get some attention, too, thanks to Elizabeth Warren. (Both because she's Elizabeth Warren and because the state is an important part of keeping a Democratic majority in the Senate.) After the disastrous legislation passed by state legislatures that flipped to Republicans in 2010, unions will also be increasing their focus on state and local races.

Voter protection and registration are clear themes emerging for union elections work this year. A coalition of unions joined in a suit to protect provisional ballots in Ohio, for instance, and the SEIU has joined with Latino groups for the Todos a Votar tour, encouraging Latinos to register and vote. The tour has already hit California, Arizona, and Florida, and is slated to be in Colorado immediately after the Democratic National Convention ends. More generally, unions like the Steelworkers are working hard to inform members about changing voter laws in their states and ensure that they know how to get their votes counted.

Workers' Voice, the AFL-CIO Super PAC, and MoveOn are joining to get out the vote, and they kicked off a grassroots canvassing effort the weekend before the Republican National Convention started, reaching 640,000 households in 23 states. Working America, the community affiliate of the AFL-CIO, will similarly be reaching out to working-class swing voters who don't belong to unions, planning to reach 1 million people directly before the election and develop voter-to-voter contact programs that will reach another million people through their friends and neighbors.

That's just the tip of a very deep voter contact iceberg, though. As in 2008, AFSCME alone is recruiting tens of thousands of activists to reach out to voters face to face. Other unions, from the Communications Workers of America to the Sheet Metal, Air, Rail, and Transportation (SMART) Workers, will also be recruiting tens of thousands more activists, knocking doors, making phone calls, and engaging online.

Fair warning: In a few cases, unions will be supporting Republicans who are unusually supportive of workers' rights. That support may come because of specific issues and specific votes, or to keep some sliver of worker-friendliness alive in a corner of the Republican Party. That may be at the local and state level, where for instance a Republican union member was elected to the New Hampshire state House in a 2011 special election, or at the congressional level, where unions like SMART like Michael Grimm, who voted with the AFL-CIO on key issues 40 percent of the time in 2012 and 45 percent in 2011, with his favorable votes clustered on issues of concern to building trades unions; SMART describes him as "a lonely but much needed voice defending the interests of working people within the tea party caucus." Those cases of unions supporting Republicans are few and far between—as few and far between as are worker-friendly Republicans, which is to say very—and, while I don't love seeing it happen, there's your explanation if you see a union supporting a Republican.

In probably 99 out of 100 races and 99.9 out of 100 doors knocked or phone calls made, though, unions will be supporting Democratic candidates. What this translates into is that millions of voters—not just union members and their families but millions more—will have one-on-one conversations about the election in the next nine weeks, centering on which candidates will govern in the best interests of workers, from workplace protections to tax policy. These efforts won't be broadcast on television, they'll be targeted to reach persuadable voters, voters who might not turn out without a good reason, and, of course, voters in key states, states that could be critical to reelecting Barack Obama or retaining control of the Senate.