Unions and the election: With friends like these... DELORES BOWIE and Audra Traynham, members of the Service Employees International Union, Local 32BJ, work as caretakers in office buildings in Philadelphia, the largest city in Pennsylvania, a pivotal swing state. But on this Tuesday, 50 days before the election, they are knocking on doors in South Philadelphia to register people to vote and to remind them, as they put it, why "we need to keep Obama." A week before the election, the two women will send postcards to everyone they canvassed reminding them to vote. The canvassing is part of the union's plan to knock on 3m doors in battleground states. It also intends to make 13m phone calls. It is especially hoping to increase Latino turnout by 20% over 2008. About half of the SEIU's 2.1m members work in the health industry, the rest in the public sector or in property services. "This is the most important election of my lifetime," says Eliseo Medina, the secretary-treasurer. We always say that, but it is true. The Republican platform is the reason why. It tries to weaken labour unions, both public and private, by encouraging legislators to pass bills that discourage them. It also wants unions to stop using collected dues for politics. Jim Hoffa, head of the once bipartisan Teamsters" union, says that those on the far right are "taking us on because they realise if they knock labour...they'll have a free run." The unions have already seen tough battles, especially in the Midwest. In February 2011 Scott Walker, Wisconsin's Republican governor, attempted to end collective bargaining for most state workers. This led to thousands descending on the state capital to protest. He survived a election, although a recent court decision struck down most of the law. In February 2012 Indiana became the 23rd state to pass a "right-to-work" law, which makes compulsory-bargaining agreements illegal. Ohio's governor tried to strip bargaining rights, too, until voters overturned the law. Mitt Romney, the Republican candidate, said he was "110%" behind this effort. He even volunteered at an Ohio phone bank. To mobilise the troops, union leaders are trying to remind members what is at stake: Medicare and Social Security as they know them, Mr Obama's health-care reform, and the continued health of unions themselves. "The subtext," says Steve Early, author of "Civil Wars in US Labour," "is "Vote Obama, he'll screw us less."" This is a pragmatic message, especially as labour is no longer as powerful as it was. Union membership has been falling for decades. According to a paper by Bruce Western of Harvard and Jake Rosenfeld of the University of Washington, published in 2011, private-sector union membership among men fell from 34% to 8% between 1973 and 2007. The authors say it is no coincidence that inequality in hourly wages increased by over 40% during the same period. Leaders have to convince their members that voting for Obama is like a flu-shot, says Lee Adler, who teaches collective bargaining at Cornell University: "It will inoculate you for a while." It is not so obvious as it once was, however, that unions and Democrats are allies. Some unionists were bitterly disappointed when a push in 2009 to legalise "card-check," by which workers can form a union if a majority sign up for it, was shot down by Democrats in the Senate. Nor were they pleased that the Democratic convention was held in North Carolina, a "right-to-work" state. Upset with the current administration, the United Mine Workers have yet to endorse Mr Obama. Democratic governors and mayors have also been taking on the unions in New York, Los Angeles and, most recently, Chicago, where Rahm Emanuel, the mayor and Mr Obama's former chief of staff, fought a lonely battle with the teachers" unions over seven days. He won his fight for an extended school year, but lost an attempt to have teacher pay more closely tied to performance. Notably, neither the president nor his secretary of education wanted to take sides in the dispute. The school reforms that the city was pursuing were close to those that Mr Obama has championed nationally; yet the president has always had to walk a careful line with the teachers" unions. He has tried to avoid poking them in the eye with his reform agenda, while at the same time pushing them to make political shifts. By focusing on reforms that are best for pupils, and by virtue of being a Democrat, not interested in union-busting for its own sake, he has achieved a great deal - for example, making teachers more accountable for performance and expanding charter schools. The unions, too, tread carefully. They know that Democrats are reluctant to get into an open fight with them, and that this can be used for political leverage. They know, too, that they can look bad when they fight the Democrats over necessary workplace reforms. Even the New York Times, no basher of unions, came out against the strike in Chicago. For his part, Mr Obama does not seem to take the union vote for granted. On September 17th he made an apparently impromptu stop at a union convention in Ohio, hours after lodging a case at the WTO against China over export subsidies for car-parts (see next story). Joe Biden, his running-mate, gave credit to union workers at a recent Michigan campaign event: "It's because of you we're coming back." Such talk will help rally union members; and those, in turn, will rally voters. Union involvement in campaigns is still crucial. They get out the vote: for every percentage-point increase in union density, voter turnout increases by 0.2 to 0.25 percentage points, and even more for minorities, according to analysis by Benjamin Radcliff of the University of Notre Dame and Patricia Davis at the State Department. Unions also spur on non-members. Indeed, when unions do not run campaigns - according to David Madland of the Centre for American Progress Action Fund - working people are 10.4% less likely to vote than other citizens; and blacks and Latinos are 9.3% less likely. Most of the people who answered their doors to SEIU's canvassers last Tuesday were Democrats, but there was the occasional Republican. Ms Bowie said she even helped one Republican to register to vote. Ms Traynham jokes that she likes to tell Republicans "Don't forget to vote on November 7th" - the day after the election.