Any rightward trending in Minnesota stalled in 2007 when the housing bubble burst. The Republicans are no longer gaining in their key areas like they used to.
For example let's compare the numbers in Wright County, which now traditionally has the largest Republican raw vote majority in the state:
1996:
Clinton 15,542
Dole 13,224
Perot 5,550
2000:
Gore 16,762
Bush 23,861
Nader 1,977
2004:
Kerry 22,618
Bush 36,176
2008:
Obama 26,343
McCain 37,779
2012:
Obama 25,741
Romney 40,466
Look at any other exurban/outer suburban counties and you'll see a similar trend. Most had barely more votes cast in 2008 than 2004, and the trend to Romney in 2012 just mirrored the rest of the state/country for the most part. While from 1996-2004 the Republican vote literally tripled and grew at more than twice the fast the rate of the increase in Democratic votes.
Meanwhile compare Hennepin and Ramsey Counties in 2000 and 2012. In Ramsey County Romney actually got less than votes than Bush 2000, while Obama received about 47k more votes for Gore (significant even if you add all all 15k of Nader's votes to the Democratic total). And in Hennepin County Obama picked up 116k votes over Gore (81k over Gore+Nader), while Romney picked up only 15k over Bush. The population shifts simply don't benefit the Republicans anymore.
Yeah, listen to BRTD on this one. Anyone who thinks that MN is continuing to drift right (as, indeed, it did in the 90s) is wrong, particularly because Minnesota is emphatically
not a rust belt state. Gore's 2000 margin, Pawlenty's 2006 victory, and Franken's teensy-tiny 2008 victory are at least partially the result of Minnesota's entertaining political environment (an unusual fondness for third parties and concomitant reaction to Ventura's 1998 victory) moreso than any indication of "trends".