There's no question that America's environmentalists won big in the midterm elections. "We picked up twenty new environmental votes in the House of Representatives and five in the Senate, plus four governorships," says Carl Pope, executive director of the Sierra Club, who called 2006 "the most successful midterm election in the environmental movement's history."

Whether the victory is big enough to change government policy during the last two years of the Bush presidency, especially on the overriding threat of global warming, is less clear. Much will depend on how worried Republicans get about running on Bush's environmental record in 2008. "Congressional Republicans will adopt an 'avoid embarrassing Bush' strategy," predicts Brent Blackwelder, president of Friends of the Earth. Now that Democrats enjoy majorities in both houses of Congress, Blackwelder adds, "they could get a decent global warming bill through the House and probably onto the Senate floor. If Republicans conclude they can't defeat the bill on a straight vote, they'll filibuster it to save Bush, and ultimately themselves, the embarrassment of vetoing it."

With a narrow 51-to-49 Senate majority, Democrats lack the votes to block filibusters, much less override vetoes. But moving strong legislation and daring Republicans to take the heat for scuttling it would enable Democrats to position themselves as the party of environmental protection and energy independence, two themes that increasingly resonate with voters across the political spectrum, analysts say, pointing to the Senate victories of organic farmer Jon Tester in Montana, Claire McCaskill in Missouri and Sherrod Brown in Ohio, all of whom spoke often about linking green energy development and economic revival.

But this scenario is plausible only if Democrats act in unison and are willing to take bold positions--no small assumptions. The temptation will be to embrace incremental measures that can attract bipartisan support rather than legislation strong enough to match the problems. Future House Speaker Nancy Pelosi and Senate majority leader Harry Reid boast strong environmental records, as do Barbara Boxer, the new chair of the Senate Environment and Public Works Committee, and Nick Rahall, chair of the House Resources Committee. But many rank-and-file Democrats have been quiet during Bush's six years of trashing environmental protections. And John Dingell, the veteran Detroit Congressman who regains the chair of the powerful House Energy and Commerce Committee, has long been Congress's most adamant opponent of increased fuel-efficiency standards for cars and trucks--a key element in any meaningful global warming policy.

Nevertheless, "going from a Congressional leadership that marched in lockstep with Bush to one led by Pelosi and Reid will mean that debates no longer start with proposals that would take us backward," says Anna Aurilio, legislative director of USPIRG. "We won't have to keep fighting to protect the Arctic National Wildlife Refugee; ANWR is safe now. Instead, we'll have an opportunity to bring forward policies that could actually solve the problems we face."

And lawmakers of both parties may now think twice before voting against the environment, considering what else happened in these elections. The Sierra Club, the League of Conservation Voters and other green groups targeted a bipartisan "Dirty Dozen" members of Congress for defeat; nine were brought down, including the man pilloried as Public Enemy Number 1: Representative Richard Pombo, the California Republican who led the charge to drill in ANWR and gut the Endangered Species Act.

"The defeat of Pombo sends a clear message to anyone who might share his ideology: When it comes to elections, the environment is now a giant killer," says Pope. Pombo had won past elections with more than 60 percent of the vote, and Pope recalls that "nobody--not the Democratic Party, not pundits, not even some of our own people--thought we could beat him." But environmental groups sent an army of volunteers to Pombo's district, made 643,000 phone or face-to-face contacts with voters and poured in $1.2 million to help elect--sweet irony--a wind energy specialist named Jerry McNerny. "The unsung hero" of the victory was former Congressman Pete McCloskey, says Pope, adding that, although McCloskey lost against Pombo in the primary, he awakened Republicans to Pombo's flaws and opened them to making a different choice in November [see Hertsgaard, "A Dragon Slayer Returns," March 27].

Pelosi promises that in the first 100 days Democrats will rescind $12 billion in tax cuts for oil and gas companies and invest it in renewable energy. But the energy that Democrats seem to have in mind is corn-based (rather than sugar- or cellulose-based) ethanol, which is as environmentally dubious as it is popular with Farm Belt politicians and the agribusiness giants who pocket the subsidies. The news is better on global warming. Boxer says she will introduce legislation modeled on the law that California recently passed requiring state greenhouse gas emissions to decline to 1990 levels by 2020. Pelosi, along with 109 others, has endorsed similar legislation, sponsored by Representative Henry Waxman of California, that includes a target of 80 percent reductions by 2050, which scientists urge to avert the worst of global warming.

If Democrats can pass either of these initiatives, they could signal to businesses, individuals and the rest of the world that a change is coming to US global warming policy. Congressional Republicans would then face a choice: Do they stick with the do-nothing policies of a lame-duck President or try to reposition themselves in the run-up to 2008? Calculations on both sides of the aisle will be influenced by the wild card of public opinion. The last year has brought a reawakening of popular and elite concern about the environment in general and global warming in particular, aided by the media attention Al Gore's movie generated. The challenge for environmentalists--allied with a growing green business constituency--is to fan that mood into a sustained bonfire that convinces incumbents they must take real action or risk retirement in 2008. In that case, the next two years might bring some surprises from Washington after all.

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