Gov. Brian Schweitzer's Big Idea - to build plants to turn coal into liquid fuel, thus reducing dependence on foreign oil while taking advantage of our coal resources before they are made obsolete by cleaner energy sources - is taking a big beating these days.

The concept, the subject of much recent congressional debate, has a couple of main problems. One is that the huge incentives involved are seen by many as a reckless boondoggle for the coal industry. The second is the fear that carbon dioxide pollution from the process may not be controllable either economically or practically.

Environmentalists have been sounding the alarm for a long time, and they've been joined by a string of big-city editorial writers. The latest assault comes from this month's issue of Scientific American magazine, which features an editorial headlined "Worse Than Gasoline."

Scientific American, a tough-minded, apolitical publication, notes that liquid coal would produce almost a ton of carbon dioxide for every barrel of liquid fuel. (The magazine doesn't mention another daunting problem - the huge amounts of water necessary to the process. Some say Montana simply doesn't have enough water for the job.)

U. S. Sen. Jon Testers' amendment to provide incentives to build coal-to-liquid plants that capture and sequester the carbon underground is welcome. We need to find out if large-scale sequestering of greenhouse gases is even feasible.

But according to the magazine, even if sequestration works, some studies say liquid coal still would release 4 to 8 percent more tailpipe global warming pollution than gasoline.

This is no time to take a Luddite stance against technological breakthroughs. Just as people who protest wind farms on aesthetic grounds are ignoring the big picture, so are those who would write off America's vast coal reserves out of hand. But before we commit untold billions of dollars toward a process that might only worsen greenhouse pollution, we need to make darn sure that this big idea is also a good idea.