But more importantly, a Nelson retirement would make an already tough map even more difficult. Democrats are defending 23 seats while Republicans are defending just ten. With Nelson in the picture, Nebraska is already a very tough hold. Without him, the task becomes a very steep uphill climb. That said, the GOP field has not overwhelmed. Frontrunning Attorney General Jon Bruning has seen his share of negative press, but he showed signs of improvement in fundraising last quarter. He faces a challenge from Treasurer Don Stenberg, who is running to Bruning's right (but has not shown any ability to raise money) and state Sen. Deb Fischer. Metrics like fundraising only tell part of the story, as outside groups on both sides will play a big role in a race that could well decide control of the Senate. The fact that the race takes place in a presidential year in a state where President Obama will struggle also bodes well for the GOP. As long as Republicans can put up a credible candidate, they will have a fighting chance in a race against Nelson. In a race without Nelson, the pickup opportunity is golden. The only thing that's clear at this point is that no one knows for certain what Nelson will do. One source close to the senator believes that he is going to run for reelection, but added, "if he woke up and said I'm not going to do it, that wouldn't surprise me either." Nelson's allies point out that he did not decide until January of 2006 whether he was going to run for reelection that cycle, so it's not as if this cycle's timeline is a major departure from past protocol. The fact that there is no clear Democratic successor makes the waiting game tolerable, if not ideal for national Democrats; it's not as if there is a young up-and-comer itching to gear up a fundraising machine and hit the campaign trail running.