Last week Andy Stern announced his resignationas president of Service Employees International Union (SEIU), America’s largest and most influential labor union. Since then there has been much speculation over his successor, with two contenders gaining prominence: Mary Kay Henry, an SEIU executive VP with a background in healthcare sector organizing, and Stern’s right-hand woman, Anna Burger (also an executive VP). The two women promise to take the union, which contributes heavily to Democratic politics and pushes for progressive policies across the nation, in very different directions, with Burger likely to stay a politically-focused course in DC and Henry promising to re-focus on organizing and building alliances in the labor movement.

At first, Burger was widely considered the favorite. She is Stern’s closest ally and she has stood with him since his emergence as an SEIU leader in Pennsylvania in the 1970s. Burger currently has responsibility for much of SEIU’s day-to-day operations, and she is officially in charge of the splinter Change to Win (CtW) labor federation, which SEIU led out of the AFL-CIO in 2005. Burger also has closer ties to the Obama administration than anyone else in SEIU (besides Stern). But news breaking this morning points to a tougher succession fight, as more than half of SEIU’s executive vice-presidents endorsed her opponent.

SEIU has eight executive VPs, including Burger and Henry, and this weekend four of them fell in line behind Henry, giving her a majority of senior leader support. Politico’s Ben Smith has the scoop, including the letter the four wrote to SEIU's executive board, the 75 member body that will vote on Stern’s successor within 30 days of his official retirement (which should come by the end of April).

More below the jump.

The letter emphasizes Henry’s “ability to build consensus”, describing her as a leader who recognizes that “our political strength comes from our two million members, not individual union leaders”. These sentiments can easily be read as a rejection of the strict top-down ethos Stern fostered within SEIU (where his strong personality easily dominated). Henry is also described as a “relentless advocate for making organizing our number one priority”, which again seems to be a repudiation of SEIU’s recent, and extremely successful, focus on electoral politics and policy. The VPs in question go on to highlight Henry’s ability to “restore our relationships with the rest of the union movement”. Under Stern and Burger’s leadership SEIU has stepped on a lot of toes, breaking away from the AFL-CIO to form the equally ineffectual CtW, and then proceeding to do battle with former partner UNITE HERE in a controversial attempt to absorb its membership. SEIU’s fight with its erstwhile ally earned Stern’s union the condemnation of nearly every other major labor union in the nation. (SEIU’s struggle with a huge breakaway California healthcare worker local, the recently christened National Healthcare Workers United, has also garnered controversy.)

However, the letter isn’t a direct repudiation of Stern’s leadership. Its authors go out of their way to praise Stern (“It’s hard to imagine the future of SEIU without Andy at the helm, inspiring us with his energy”, etc.) and it doesn’t mention Burger by name. SEIU spokesperson Michelle Ringuette played down the significance of the letter, placing it in the context of the overall conversation over the union’s future: “This isn’t an unusual thing whatsoever…it would not be an isolated action.”

It remains to be seen how much influence these five VPs, including Henry, will have on the executive board. The differences between the two women are real enough, although it is impossible to say how radically they would alter SEIU's internal dynamics. Burger’s recent duties have primarily been DC-based and heavily political and it is likely that she would continue in this vein as president. After all, she already has the relationships to build on. It is unclear how much Henry’s supposed emphasis on organizing will matter—organizing workers remains hellishly hard—but her ability to unify the labor movement, and cease SEIU’s war with UNITE HERE, could be aided by her distance from Stern.

A Burger victory would certainly be seen as an extension of Stern’s reign, and would probably result in the union’s activities unfolding along smiliar lines. But a Burger victory could be tough to pull off, because of her close relationship to the out-going president: she has to carry all the controversies of his term, without the immense charisma and influence that Stern himself commanded. The fact that Henry felt comfortable enough to challenge Burger, and that four VPs have endorsed her, shows that Burger’s campaign isn’t ironclad.