This is great news. Dayton probably would have been in the fight of his life for re-election anyway, and no doubt he'd have taken some heat for being the only senator to close his DC office. I think we will see Mark Kennedy getting into this race sooner rather than later.
The GOP has to be happy about their chances of winning this open seat.
Kennedy has been building up a warchest for this seat since he first got into the House in 2002.