The League of Conservation Voters has released a "2008 Presidential Primary Voters Guide" that focuses on the Democratic and Republican Party presidential candidates and their positions on global warming. The guide summarizes the positions of the candidates for the two parties nominations by stating that:

"In the race for the Democratic nomination, all of the candidates have shown a commitment to addressing global warming. Senators Biden, Clinton, Dodd, Obama and Rep. Kucinich have co-sponsored the strongest global warming bills in Congress. Each of the top-tier candidates, including Gov. Richardson and Sen. Edwards, have put forward aggressive plans to reduce greenhouse gas pollution by at least 80% below 1990 levels by 2050. The differences between these plans are detailed herein. On the Republican side, the differences are much more stark. With the exception of a few of the more fringe candidates, each candidate has acknowledged that global warming is a problem. But that is where the similarities end. Sen. McCain has offered legislation to reduce global warming pollution by 65% by 2050. None of the other Republican candidates--Mayor Giuliani, Sen. Thompson, Govs. Romney and Huckabee and Rep. Paul--have offered any kind of comprehensive plan to address global warming. Moreover, aside from Sen. McCain, only Gov. Huckabee has signaled support for a cap on emissions. Again, aside from the long-standing commitment of Sen. McCain, the rhetoric of the other Republican candidates has improved through this long year of campaigning. But as a cautionary note: then-Governor George W. Bush said in 2000 that he considered the leading greenhouse gas, carbon dioxide, to be a pollutant that should be regulated, then spent his entire term in office trying to stop and subvert efforts to do just that."