Instead, the two appeared at an energy and environment forum in Seattle, promoting action on global warming and investing in renewable energy.
'The Northwest can lead the way to get off of our overdependence on foreign oil, to grow the economy, protect the environment and have a better foreign policy,' Cantwell said.
That showing prompted Republican challenger Mike McGavick to appear with Idaho Senator Larry Craig at a local damn, which he accused Cantwell of wanting to breach.
They are not the only ones talking big about the environment this election, as a new and odd coalition has brought the issue to the forefront of US politics more than ever before.
The Sierra Club, one of the nation's largest environmental activist groups, gleefully stated this summer that energy and environmental issues have been placed at the 'forefront of election year politics.'
But it is not climate change per se that is regularly placed in the spotlight.
Instead, the words renewable energy, conservation, energy efficiency, protecting natural resources and America's 'heritage' are being emphasized by a variety of candidates across the political landscape in the run-up to local, state and congressional elections on November 7.
Motivation for the new rhetoric stems primarily from economics (high petrol prices), national security (dependence on foreign oil), and in part a desire by some politicians to distance themselves from an unpopular president, George W Bush.
California's Republican governor Arnold Schwarzenegger is a seemingly passionate environmentalist, but his stance has also proven a vote winner that bolstered his moderate credentials in a heavily Democratic state. Schwarzenegger signed three bills in September mandating caps on greenhouse-gas emissions and the use of renewable energy.
'Certainly a number of governors see green economic development as a winner,' Judi Greenwald, director of innovative solutions at the Pew Centre on Global Climate Change, a non-partisan think-tank, told Deutsche Presse-Agentur dpa. 'A lot of states focus talk about environment in a way that's connected to economic development.'
Americans seem to like the idea of environmentally friendly economic development. A Los Angeles/Bloomberg poll over the summer showed 52 per cent chose renewable energy as the best way of weaning the US off its foreign energy dependence. Only 20 per cent favoured the environmentally unfriendly option of drilling for more oil or gas.
Environmental groups are getting the message. Instead of focusing solely on the dangers of global warming - their primary goal - many are tailoring their own language and campaigns to better impact the prevailing debate.
'The only way we are going to be able to make progress on (global warming) right now is if we can make the economic argument and not just the environmental,' David Willett of the Sierra Club told dpa.
Aside from the new set of motivations, the Sierra Club and its partners have found a surprising new ally in the so-called Christian Right - an amalgam of groups long identified with Bush's conservative Republican party.
A group headlined by the recently elected president of the Christian Coalition, Reverend Dr Joel Hunter, as well as some board members of the National Association of Evangelicals (NAE), launched a Call to Action campaign last month including radio ads and a film documentary to advocate action on global warming among churches and congregations.
That follows the 'Evangelical Climate Initiative' launched in February and signed by 86 leaders of the Protestant Evangelical community. Evangelicals make up one quarter of US citizens, and in 2004 voted by a ratio of 4 to 1 for President Bush.
'We have to become the change agents within the Republican Party, and I believe we can and will,' Reverend Richard Cizik, Vice President of the NAE, told public broadcaster PBS.
But while the new policy does not have everyone's support in the coalition, the shift, as well as the focus on energy rather than global warming per se, has allowed moderates in the Republican party - traditionally more opposed to action on the issue than Democrats - to speak out in favour of new initiatives.
The Christian Right's concerns are 'starting to be heard' in Congress, where Republican leaders have so far tried to protect moderates from having to stake out a position, according to a congressional observer who spoke on condition of anonymity.
Another aspect: local initiatives on climate change have begun to bubble up around the country in lieu of federal regulation, and here the movement is of a much less partisan nature than at the federal level.
The mayors of more than 300 cities have signed an agreement committing them to reduce greenhouse gas emissions to the levels prescribed by the Kyoto Protocol, an international climate change agreement which the United States is not a part of.
Many states have adopted similar targets and a number of regional state initiatives are seeking to introduce a cap-and-trade system on specific industries, such as power plants, by which companies emitting higher pollution levels can purchase credits from cleaner competitors.
California's bill in September made the state the first to impose mandatory statewide limits on greenhouse-gas emissions, punishable by fines. That makes California the greenest state in the land - not unsignificant given that California alone is the world's tenth largest polluter.