In the wealthy swing districts of Minneapolis’ western suburbs, the gay marriage amendment that will appear on the 2012 ballot lands outside voters’ chief concerns of taxes, education and the overall health of the economy.

In many cases, DFLers simply got caught in an undertow in districts that are fundamentally split in their political allegiances; in some, like rural Senate District 16, they handed back control of districts no one had expected them to win in the first place; in others, it appears, they failed to take steps to protect incumbents who faced discernible pockets of Republican opposition.

Minnesota political observers were surprised by the DFL’s walloping performance at the polls in Tuesday’s state House elections. “I knew there would be Democratic gains ...