WASHINGTON -- Massachusetts Gov. Mitt Romney on Dec. 16 made a significant move that will benefit the pocketbooks of his state's consumers and perhaps boost his own Republican presidential prospects. He pulled Massachusetts out of the compact of Northeastern states requiring a reduction in power plant emissions of carbon dioxide.

 The Regional Greenhouse Gas Initiative (RGGI) would cut the emissions by 10 percent by 2019, forcing up electricity prices because of greater dependence on increasingly expensive natural gas. This Northeastern initiative, spearheaded by a Republican, New York Gov. George Pataki, is viewed by environmentalists as foreshadowing national limits. It is an end run around President Bush's opposition to mandatory reductions. During early December negotiations in Montreal on the Kyoto pact, European Greens praised RGGI as a repudiation of President Bush's dismissal of global warming alarmists.

 The defection of Romney, originally inclined to support RGGI, represents a major setback for the Greens. Sen. John McCain, an advocate of national carbon limits, runs far ahead of Romney in early Republican presidential polls. But on this as on tax policy, McCain conflicts with not only Bush but also the Republican consensus. McCain's proposal for national mandatory carbon limits has been rejected by the Republican-controlled Senate, most recently, 60 to 38, in June. In contrast, Romney may have a leg up in coal-producing states. He also is attracting interest from automakers and other industries that oppose mandatory CO2 limits.

 The ungreening of Mitt Romney has provoked screams of protest in blue-state Massachusetts. "For those in Congress who have fought the Bush administration," said Democratic Rep. Martin Meehan, "it was heartbreaking to watch the Romney administration attempt to dismantle efforts to reduce carbon dioxide emissions in the Northeast."

 While Meehan called it a "national embarrassment for Massachusetts," both industrial and consumer interests in the state stand to benefit from Romney's apostasy. The governor grew skeptical of RGGI after first showing interest in the compact, and late in September he convened a high-level meeting with industrial and environmental interests in Boston. The industrial representatives told the governor he would face continued economic decline in Massachusetts if he did not reject the compact. The Greens told Romney that RGGI was just the first part of a national plan to fight global warming.

 Carbon limits necessarily force greater reliance on natural gas for electric power, applying further pressure to boost prices. The per million BTU price soared to an astronomical $14.80 in Dec. 14 trading, though the price since then has dropped to $11.10 on Dec. 30.

 Everybody agrees that carbon limits will force up electricity prices steadily far into the future. The disagreement is over how much the costs will go up. A study done for RGGI shows the cost per consumer rising $34 a year every year for 20 years, but business groups call that number laughable in view of how much CO2 caps really will cost. That is unnerving for Massachusetts, which now has the nation's highest electric power bills. However, the bigger impact could be on the cost to industries that threatens the loss of jobs.

 Romney's concern over carbon caps is shared by other Northeastern governors. Republican Donald Carcieri of Rhode Island, Republican Robert Ehrlich of Maryland and Democrat Ed Rendell of Pennsylvania also took their states out of RGGI conformity. But the governors of Connecticut, Delaware, Maine, New Hampshire, New Jersey, New York and Vermont are still in the compact, ready to impose a heavy economic burden on their citizens. Outside the Northeast, the states of California, Oregon and Washington also are moving toward carbon caps.

 Green pressure can lead politicians to make promises that they would regret. It happened to George W. Bush at Saginaw, Mich., in September 2000 when he took a position hardly noticed at the time. "We will require all power plants to meet clean air standards in order to reduce emissions of sulfur dioxide," he said. That never really was Bush's position, but it led to a misunderstanding between the president and his first Environmental Protection Agency administrator, Christine Whitman, that haunts him to this day. It appears Mitt Romney will avoid that pitfall on his long uphill climb to the White House.