The Service Employees International Union plans to pass on making a gubernatorial endorsement in advance of the Minnesota's DFL primary, a source tells the Star Tribune.

The absence of a nod from the politically active union, which has tens of thousands of Minnesota members, takes away a powerful symbol and concrete tool from the DFL candidates -- Margaret Anderson Kelliher, Mark Dayton and Matt Entenza -- vying for voters' August nod if SEIU stays out.

Kelliher and Dayton both already have union endorsements. But backing from SEIU would have given them momentum in the push toward the primary and provided ammunition for the crucial ground game this summer.