Senator Lamar Alexander (R-TN) – Has introduced legislation in the past that would limit global warming pollution from power plants; as a member of the Senate Republican leadership the question will be - does he help the Republican caucus move to a more responsible position?

Senator Evan Bayh (D-IN) – A moderate Democrat with good environmental ratings from the League of Conservation Voters; represents state with one of the largest per-capita manufacturing industries in the country; he will look to balance economic and manufacturing interests in the bill.

Senator Jeff Bingaman (D-NM) – Chair of the Senate Energy and Natural Resources Committee; has his own competing global warming legislation with Senator Arlen Specter (R-PA); is looked to by many moderate Democrats, particularly those with coal mining interests, as a leader on issue.

Senator Lindsey Graham (R-SC) – Senior Senator from South Carolina, a state vulnerable to hurricanes and coastal flooding; is one of Senator John McCain's strongest allies in the Senate; supports nuclear power and will try to boost support for nuclear energy in the bill.

Senator Claire McCaskill (D-MO) – Freshman Senator from a state that is a traditional political bellwether for the country; has said that global warming is a serious threat and has promoted investments in alternative energy; her senior Senator, Kit Bond, is one of the Senate leading opponents against action to reduce global warming emissions; will look for ways to best balance her state's rural and low-income interests in the bill.

Senator Harry Reid (D-NV) – As Senate Majority Leader, he has scheduled floor time in early June to debate the Lieberman-Warner Climate Security Act; his leadership will be critical in bridging the differences between members.

Senator Ken Salazar (D-CO) – First-term Senator from a state vulnerable to droughts and wildfires that could be made far worse by global warming; Colorado has abundant solar and wind energy resources, but also large coal and other fossil fuel reserves; Salazar has praised Colorado Governor Bill Ritter's Climate Action Plan, which adopts aggressive greenhouse reduction goals; will be looking at various technology incentives and opportunities for agriculture in the bill to make sure that they work for Colorado.

Senator Gordon Smith (R-OR) – Second-term Senator from a state renowned for its natural beauty and diverse geography; Oregon is part of the Western Climate Initiative to establish a regional approach to reducing global warming pollution; he continues to question the science behind global warming. Will he decide to represent the citizens of his state and join the call for real action?

Senator Arlen Specter (R-PA) – Fifth-term moderate Republican Senator from a political swing state with manufacturing and coal interests; has his own global warming legislation with Senator Jeff Bingaman (D-NM); if Senator Bingaman and Senator Specter will both work with constructively with Senators Lieberman and Warner on key areas of interest, it will send a strong signal to other undecided votes.

Senator John Sununu (R-NH) – First-term Senator from a state with big outdoor recreation and skiing industries that could be vulnerable to global warming; in 2005, New Hampshire joined the Regional Greenhouse Gas Initiative of nine Northeast and Mid-Atlantic states to limit global warming pollution; while Senator Sununu has supported a bill that would limit emissions from powerplants, he voted no on a comprehensive cap-and-trade bill in 2003; despite strong support for addressing climate change in the state, he has yet to endorse the Climate Security Act.