Legislation Requiring Reductions
A very large majority favors legislation requiring reductions in greenhouse gasses. A very large majority of Americans (8 in 10) say they support the targets of the McCain-Lieberman legislation (Climate Stewardship Act) that call for large companies to reduce their emissions of greenhouse gases to 2000 levels by 2010 and to 1990 levels by 2020. Two-thirds say they favor the legislation even if there are significant increases in the cost of energy. A modest majority says that if a candidate favors legislation requiring reductions in greenhouse gas emissions, this will increase the likelihood they will vote for that candidate; only a very small minority says that it would decrease the likelihood. Those in favor of taking steps are more likely to have their vote influenced by a candidate's position than those opposed.
A key controversy is over whether the US should rely on voluntary measures to reduce greenhouse gas emissions or if the US should legislate requirements for reductions. The most prominent legislation requiring such reductions of the Climate Stewardship Act, also known as the McCain-Lieberman bill named after the Senators that have sponsored it.
A very large majority of Americans say that they support US legislation that would reduce greenhouse gas emissions. PIPA introduced respondents to the Climate Stewardship Act, and told them about the targets for greenhouse gas emissions called for in one of the key drafts, which requires large companies to reduce their emissions to 2000 levels by 2010 and to 1990 levels by 2020. In June 2005, PIPA asked "based on what you know, do you favor or oppose having such limits on how much greenhouse gases large companies can emit" An overwhelming majority of 83% favored it with just 13% opposed. In June 2004 81% said they favored such limits with 16% opposed. 
Americans also appear to be ready to accept significant costs in support of the legislation. First, respondents were told that "According to an estimate done by MIT, cutting greenhouse gas emissions as much as this draft of the new bill would require will increase various costs to the average American household by about $15 a month." (See Appendix A) They were then asked how they felt about this estimate. The response was neutral overall, with a plurality of 38% assuming that it is "approximately correct" and nearly as many saying that it seems on the high side (28%) as saying it seems on the low side (27%). 
They were then asked if they would favor the bill "If in fact it appears that it would likely cost $15 a month for an average household." Two out of three (68%) said they would, while 28% said they would not. Democrats were just slightly more willing to accept the $15 cost (72%) than Republicans (67%). This support was virtually unchanged from June 2004, when 67% said they would accept costs of $15 a month. Only 28% said they would oppose it. 
In June 2004, people were also asked whether they would support the legislation if the actual costs were slightly lower or slightly higher. Asked "if further research concluded that it would likely cost $10 a month for an average household, would you favor or oppose enacting such a bill" a strong majority of 75% said they would favor the CSA. On the other hand, asked "if further research concluded that it would likely cost $25 a month for an average household, would you favor or oppose enacting such a bill" support drops to 40%, with 57% opposing the enactment of the CSA. 
Support for Politicians Who Seek Action
A modest majority says that if a candidate favors legislation requiring reductions in greenhouse gas emissions, this will increase the likelihood they will vote for that candidate, while only a very small minority says that it would decrease the likelihood.
In June 2004, PIPA also asked how it would affect the likelihood that they would vote for a candidate for political office if he or she "were to favor a law requiring large companies to gradually reduce their greenhouse gas emissions" and asked to answer "on a scale of +5 to -5, with +5 meaning that it will greatly increase the likelihood you will vote for the candidate, -5 meaning that it will greatly decrease the likelihood you will vote for the candidate, and 0 meaning that it will have no effect either way." A modest majority of 52% gave a score above zero; much more than the 12% which gave a score below zero, while 33% gave a score of zero. Overall the mean score was 1.12. 
It is worth noting that Americans were more willing to support a candidate that favors the Climate Stewardship Act regardless of party affiliation, though as one might expect, Republicans were less likely to support such a candidate than Democrats and Independents.
Perhaps more significant, the more a person believes that the problem is real and pressing, the more likely it is to affect their vote. Among those who think global warming does not require taking steps right now, 48% say that a candidate's position on climate change will affect their position, with 31% saying that if a candidate favors emission-reducing legislation this will decrease the likelihood they will vote for the candidate and 17% saying that it will increase the likelihood-a net effect of minus 14%. Among those who think that gradual steps are required, 60% percent say that it will affect their vote, with 53% saying that favoring such legislation will make them more likely to vote for the candidate and just 7% saying it will make them less likely-a net effect of plus 46%. Among those who say that the problem requires serious action, a remarkable 85% say that it will affect their vote, with support for such legislation producing a net effect of plus 67%.
When asked about hypothetical candidates Americans also show support for those who express concern and seek action on global warming. In the Mellman Group's September 1998 poll, 58% said they would view "a candidate for political office" who "spoke out in support of reducing the threat of global warming" as "forward-looking and speaking to a real problem," while only 23% said they would view such a candidate as "too interested in environmental issues and ignoring bigger problems." 
However, it does not appear that most voters regard this issue as decisive. When asked to assume that "you agreed with a particular candidate on most issues and were of the same political party, however, that candidate voted against efforts to reduce the threat of global warming," a plurality of 41% said they would still be likely to vote for that candidate, while 38% said they would not. Nonetheless, the fact that 38% said they would change their vote over this issue is still quite high.