Until recently, the environment was a bipartisan issue. Consider:

• The EPA became a cabinet-level agency during the Nixon administration.
• The 1990 amendments strengthening the Clean Air Act were adopted by a 89-11 vote in the U.S. Senate.
• Previous sponsors of climate legislation to cap emissions of greenhouse gases were Senators McCain [R], Warner [R] and Lieberman [D-I].

Conservative and conservation, after all, derive from the same root.

Regrettably, the climate issue isn't bipartisan anymore. The Waxman-Markey climate bill passed the House with just eight Republican votes, and with 168 Republicans in opposition. Republican senators haven't had anything nice to say about the Kerry-Boxer proposal in the Senate, as far as I can tell.

This raises several questions.

1. Why has the climate-change issue become so partisan?
2. What, if anything, can be done to persuade Republicans to support strong measures to deal with global warming?
3. Finally, why aren't big companies that support climate legislation pushing their Republican friends in Congress to contribute to the debate?

Congressional Republicans deserve some blame for being missing-in-action on the climate change legislation. During a webinar that I moderated last week for The Energy Collective (an excellent summary can be found here), Manik "Nikki" Roy, the politically savvy vice president of the Pew Center on Global Climate Change, said: "The Republican leadership and the base and the echo chamber, their default assumption is that they are not going to help President Obama deliver on any of his major initiatives." There is some truth to this and it's dismaying. People are elected to the Senate to serve the nation, not to play politics with life-and-death issues like climate and health care.

The thing is, as Nikki noted, a slew of Senate Republicans -- McCain, Lamar Alexander, Lisa Murkowski, Bob Corker, Judd Gregg, Olympia Snowe and Susan Collins -- have either written, co-sponsored or voted for greenhouse gas legislation before. "There are several others who might engage on the issue," Nikki said. But conservative bloggers and talk-show hosts stand ready to punish cooperative Republicans for supporting government regulations that they view as creeping socialism or worse. See, for example, Michelle Malkin on the Boxer-Kerry bill.

Obama's green team hasn't helped matters, either. Climate czar Carol Browner, EPA chief Lisa Jackson and White House staffer Nancy Sutley are former Clinton administration officials who see the world through a partisan lens and are thought to have an anti-business tilt. (The EPA, for instance, is said to be pulling back on programs that recognize companies for environmental leadership because senior officials want to focus on enforcement of environmental laws.) Obama himself hasn't reached out to Republican leaders on climate. To the dismay of enviros, his actions suggest that climate ranks no higher than No. 4 on his to-do list, behind the economy, health care and Afghanistan/Iraq.

Having said that, there are ways to break the partisan deadlock. One is to make nuclear energy part of the climate solution. Right now, there's only minimal support for nukes (in the form of worker training) in the Boxer-Kerry bill. Pew's Nikki Roy says that support for nuclear, perhaps in the form of loan guarantees for new plants, "is absolutely part of the political solution because we need Republican votes, and swing Republicans are very interested in nuclear power."

Imagine, for a moment, a bill that for the next decade or so substantially raised the cost of burning conventional fossil fuels (through cap-and-trade or a carbon tax) to encourage fuel switching from coal to natural gas, which is cleaner and appears to be increasingly abundant. You might lose some coal state Democrats but, interestingly, that was the case in 1990 when Byrd and Rockefeller opposed the 1990 Clean Air Act that forced the coal industry to clean up its act.

In the meantime, the government could set the stage for a true clean-energy revolution by promoting an array of long-term alternatives (ideally, without picking winners or losers or tilting the playing field) and let the market see which ones emerge. The would include solar, wind, geothermal, nuclear or so-called clean coal.

McCain, among others, is a strong supporter of nuclear and he might find it hard to oppose a climate bill that took nuclear power seriously. "McCain's just waiting for the phone to ring," a well-informed Washington observer told me last week. Of course, that would require Obama and pro-nuke energy chief Steven Chu to persuade Kerry and Boxer to open the door for nukes.

This is where business groups like the U.S. Climate Action Partnership can play a constructive role. Companies like GE, Exelon and NRG (all believers in nukes) should be pushing their Democratic and Republican allies to craft a climate bill together. They know a well-crafted federal law is better than regulation by the EPA or by the states. (These companies also need to do more to neutralize the opposition to climate legislation from The U.S. Chamber of Commerce, a topic I hope to address later this week.)

Aside from the fact that a bill without Republican support will be very hard to get through the Senate, there's another very good reason for Obama to take a bipartisan approach: When climate regulation begins and some things go wrong, as they surely will, both Democrats and Republicans will own the problems, and both will feel obligated to fix them–as opposed to lay blame.

Politically, Obama and the Republicans have a lot to gain by demonstrating that they can work together on climate, even at the risk of losing the far left and the far right. After all, the goal here is not merely a piece of legislation. It's the transformation of the energy economy. That's too big a job for any one party to take on alone.

GreenBiz.com Senior Writer Marc Gunther is a longtime journalist and speaker whose focus is business and sustainability. Marc maintains a blog at MarcGunther.com. You can follow him on Twitter @marcGunther.