Republican presidential hopeful John McCain is far and away the GOP candidate most committed to addressing global warming and the nation's energy challenges, according to the 2008 Presidential Primaries Voter Guide released this week by the League of Conservation Voters.

The voter guide, which takes a critical look at candidates' plans for dealing with global climate change, makes clear that collectively, the Democratic candidates have outlined more comprehensive and aggressive plans than any presidential candidates in history and have made a point of telling primary voters that combating global warming is a top priority. Among Republicans running for president, the guide says, "Sen. McCain holds the distinction of being the only candidate to make global warming a part of his campaign agenda and to regularly address it on the campaign trail."

On the Democratic side, all of the candidates competing for the presidential nomination have shown strong commitment to addressing global warming, though the details of their plans differ. Sens. Joe Biden, Hillary Clinton, Chris Dodd, Barack Obama and Rep. Dennis Kucinich have co-sponsored the strongest global warming bills in Congress. Each of the candidates, including Gov. Bill Richardson and former Sen. John Edwards, have proposed comprehensive plans to reduce greenhouse gas emissions by at least 80 percent by 2050.

Click here to read the full voter guide.