Josh Marshall's Talking Points Memo does an average of polls, Polltracker, that shows the Democrats losing their Senate majority, as of now.
2012 was destined to be a tough year for Senate Dems, since they would be defending about twice as many seats as the Republicans, thanks to the Democratic wave election of 2006 that recaptured the Senate majority.
Democrats now have 53 seats (counting LIEberman and Sanders), so if they lose net-four, Mitch McConnell will be running the Senate in 2013 in much the same way John Boehner has been running the House in this Congress.
How it could happen, below.
In Nebraska (Democrat Ben Nelson retiring), Polltracker has former Democratic Sen. Bob Kerrey being creamed by state Sen. Deb Fischer, 57.3-34.7.
In Missouri, Polltracker has former Republican State Treasurer Sarah Steelman way in front of incumbent Democrat Claire McCaskill, 48.7-40.7.
In the open seat in Virginia (Democrat Jim Webb retiring after one term), Polltracker has former GOP Senator/Governor George Allen ahead of former Governor Tim Kaine by 43.9-41.2.
In Florida, Polltracker finds two-term Democratic Sen. Bill Nelson trailing former GOP Sen. Connie Mack, 43.8-37.5.
In Montana, Polltracker has freshman Democratic Sen. Jon Tester narrowly behind Rep. Denny Rehburg, 49-47.
In North Dakota (Democrat Kent Conrad retiring), Polltracker has not posted an average in the reportedly (and surprisingly) tight race between Democrat Heidi Heitkamp and Republican Rep. Rick Berg. But with Romney likely to win the state by double-digits, this will be a tough hold.
There are also close contests for currently Democratic open seats in Hawaii and Wisconsin.
Overall, it seems likely (now) that Democrats will lose at least four seats they hold now, and their hopes to barely hold the majority will depend on winning at least one of three current GOP seats -- Elizabeth Warren in Massachusetts (essentially a tie now, according to Polltracker), Shelley Berkley in Nevada (down 1.4 to Dean Heller now), and convincing the very independent Angus King in Maine (a sure winner) to affiliate with Senate Democrats.
That's a pretty delicate balance, and there's a big thumb on the scales -- tens of millions from dedicated billionaires and other aggrieved white people, directed by political pros like Rove to Republicans in the swing Senate races.
Please do what you can to offset that with your credit card love.
Also, most Kossacks live in or near important Senate states -- Virginia, Florida, Massachusetts, Nevada, Wisconsin, etc. -- and can help out on the ground.
For example, I live near Albany, NY, and will be spending several fall weekends in nearby Pittsfield working for Elizabeth Warren.