"They are greener than any other group" of Millennials, says della Volpe, who compares them to traditional New England Catholics, historically solid Democratic voters despite strong disagreements with the party over abortion and other issues.
In 2004, the religious-center Millennials split their votes evenly between George W. Bush and John Kerry. Just four years later, della Volpe believes, they voted "overwhelmingly for Obama," though he does not yet have the final numbers. (Harvard's IOP will be releasing a report on Millennial voting later this month.)
The environmental-legislation debate, if it divides the parties as cleanly as expected, could go a long way toward making the GOP unpalatable for those voters.
If the GOP keep this up, notes Teixeira, "It probably will be true that this generation will be locked in with the Democratic Party for years — and completely out of reach for the Republican Party."
Of course, Democrats have a long history of screwing up golden opportunities. And they could do it again.
Millennials' Democratic leaning is not yet set in stone. In fact, says Peter Lawrence, director of CIRCLE (Center for Information & Research on Civic Learning and Engagement) at Tufts University in Medford, just a couple of years ago, Democrats had only a slight advantage among Millennials.
And Millennials are not yet moving in large numbers toward registering, or self-identifying, as Democrats, adds della Volpe.
"This generation has quite a lot of cynicism about political institutions," says Teixeira. "Even though they have the initial approval of this group. . . . Democrats have to show this generation that they are not just the same-old, same-old."
Which is exactly what could happen if Democrats fail to follow through on global warming.
For now, the House appears ready to move swiftly and aggressively on the far-reaching ACES bill, currently running 648 (tree-killing) pages, which some expect to pass by Memorial Day. But already there are signs that Democrats in the Senate, and Obama himself, may be leaning toward moving much more slowly on the issue.
Rasky, who is following the issue closely, says that the hesitancy about going for the jugular here lies with Democratic senators from "brown states" — those heavily reliant on old-fashioned, coal- and gasoline-based manufacturing, like Michigan, Pennsylvania, Ohio, and West Virginia. Those lawmakers are reluctant to move too quickly on reduction of greenhouse-gas emissions, particularly in the form of "cap and trade," the approach incorporated in Markey's bill. (See "Cap and Trade Explained" sidebar.)
California Senator Barbara Boxer, who chairs the Environment and Public Works Committee, has also indicated that, rather than vote on the House bill, she will set up her own study groups — and possibly not emerge with a bill until next spring. Obama, who tried unsuccessfully to include cap and trade in the recently passed budget, has been notably quiet about the issue.
That has led to growing concerns that the legislation might be watered down to ensure passage. Cap and trade might come out altogether; huge exemptions might be given; target reductions might be modified. Many on the left are complaining — Robert F. Kennedy Jr., a prominent voice on the environment, has blasted the bill for including so-called clean-coal technology.
"Democrats have a problem," says Levine, "because young people are more optimistic about finding solutions. So if they fail, young people would be very disappointed."