With climate legislation stalled in Congress and U.S. EPA just months away from regulating greenhouse gases for the first time, 37 states have taken sides in a court battle that could end up steering U.S. climate policy for years.

Just like the cap-and-trade bills that narrowly cleared the House and floundered in the Senate, challenges to the Obama administration's climate program have highlighted a bitter divide between industry-heavy states and their environment-minded counterparts. All of them are now lined up for a high-stakes legal showdown that will allow a few federal judges to decide what 535 members of Congress have not.

The states involved in the litigation are closely divided. Seventeen are asking to review EPA regulations, while 20 are supporting one or more EPA rules, according to a Greenwire analysis of federal court records. Thirteen states have not taken a side.

Pat Parenteau, an environmental law professor at Vermont Law School, said he cannot think of any environmental case that has gotten so much attention from the states. Just more than 20 states got involved in Massachusetts v. EPA, the 2007 case in which the Supreme Court ruled that EPA had to consider regulating greenhouse gases under the Clean Air Act.

One reason is that the political stars have aligned to make environmental regulations a hot-button issue on the campaign trail, Parenteau said. And while the Supreme Court's 2007 decision had huge implications for the states, "the stakes are higher here," he said. "After all, we are talking about all of the major economic sectors being affected by these regulations."

Though it is only in the preliminary phase, the court battle is already daunting in terms of paperwork. About 90 legal challenges to the climate program have been filed so far, drawing filings from more than 140 businesses, trade groups, advocacy groups and lawmakers.

Lawmakers were warned about this scenario, experts say.

Rep. John Dingell (D-Mich.), one of the architects of the Clean Air Act, often told his colleagues that if they did not reach an agreement, the climate debate would become a "glorious mess" of regulations and litigation. That is where things are headed now, said Eric Pooley, the deputy editor of Bloomberg BusinessWeek, during a Washington, D.C., panel discussion last week on the future of U.S. climate policy.