CNN/Money reports that cap-and-trade advocates are having such a hard time attracting support for the legislation because the Left and the Right are so far apart on energy issues. Every deal-sweetener that might tempt a Republican over to the Dark Side has the potential to repel Democrats:

For example, the nuclear industry is looking for upwards of $100 billion in loan guarantees that would go toward building approximately 20 new plants. Long-term ambitions are even bigger. Some Republicans in Congress want up to 100 new nuke plants built over the next few decades.
But, at the same time, adding too many nuclear goodies hurts the legislation’s chances.
“It would risk favoring nuclear over everything else,” said Divya Reddy, an energy policy analyst at the Eurasia Group, a political risk consultancy. “The outlook for eventual passage is looking weaker and weaker.”
That doesn’t bode well for the Obama administration, which hoped to have a deal at least in the works before heading to Copenhagen next month to hammer out a global greenhouse gas treaty.
As for increased oil drilling, the ban on offshore drilling has already expired. Although it could be reinstated with a stroke of the president’s pen, Reedy said pro-drilling advocates may be better off simply pushing for a permanent OK in a separate energy bill rather than tangling it up with global warming. Plus, the type of access staunch drilling advocates are looking for – off Florida’s west coast and in Alaska’s wildlife refuge – would be too much for many Democrats to support.
And still, even if broad access to drilling and many more nuclear plants were offered, some lawmakers opposing greenhouse gas laws would remain unconvinced the current bill is a good idea.
“The Democrats could offer bags of gold,” said Thomas Pyle, president of the Institute for Energy Research, a free-market-oriented think tank. “There’s just nothing that would make cap-and-trade easy to swallow.”