Michigan Republican Rep. Dave Stockman denounces it as "pork barrel." Illinois Republican Sen. Charles Percy warns that it's as bad as 10 Chrysler bailouts. And Sen. Gary Hart (D-Colo.) says its like setting a prairie fire to cook a sage hen.

Nothwithstanding the nasty rhetoric, the synthetics fuel bandwagon is rolling over the opposition in Congress.

The opponents are an improbable collection, and powerful. Despite past differences, the big oil companies are arm-in-arm with environmentalists like the Sierra Club, Common Cause with the Chamber of Commerce, liberals with conservatives, all of them against synthetic fuels.

But last week, after months of debate, the Senate passed a $20 billion bill to spur development of oil and natural gas from coal, tar sands, and oil shale. In June the House passed a similar, though less ambitious bill, and both are headed toward conference.

Chairman Henry M. Jackson (D-Wash.) of the Senate Energy Committee hailed the Senate bill as "the largest single energy enterprise in the history of the country."

He's right. The Senate bill promises $20 billion for synfuels right away, and $68 billion more in five years if Congress agrees. The $88 billion would be twice the worth of Exxon, one of the nation's largest corporations.

The Senate and House bills also call for creation of a quasi-public Synthetic Fuels Corp. to dole out billions in loans, purchase guarantees, grants, joint ventures and loan guarantees to the nascent synfuels industry. As proposed by President Carter last July, the corporation would be financed from the oil windfall profits tax.

As envisioned by the Senate, the synfuels plan would spur the production of 1.5 million barrels of synthetic fuel a day by 1995 -- equal to about 18 percent of the nation's current oil imports.

More important, backers such as Jackson say that it would put the nation on the path toward curbing oil imports and lowering energy costs.

The legislation has profited handsomely from outside events. The turmoil in Iran boiled over in time to boost the measure comfortably over the top in the Senate, after gasoline lines this spring propelled the House version to victory in June, 368 to 25. Said Rep. Millicent Fenwick (R-N.J.), who voted with the majority: "Voters want action on energy; they don't really care how much it costs."

Underlying the synfuels debate is a set of deep-seated issues that cut across the ideological and regional biases that usually shape congressional alignments:

Can the oil companies alone solve the nation's energy supply problem, or does the government have to coerce the industry?

Will the free market provide adequate incentives to develop alternatives to imported oil, or do the taxpayers have to assume the risk of developing new technologies?

Will the oil companies hold back on synthetics waiting for higher prices?

Attempting to answer these questions, many lawmakers found themselves in unfamiliar positions.

New Mexico's usually consistent advocate of freebooting private enterprise, Republican Sen. Pete Domenici, backed the fullblown Senate bill. "Those who want a total reliance on the market are saying, 'What's good for Exxon is good for America,'" he explained.

Another longtime oil company partisan, Sen. J. Bennett Johnson (D-La.), likewise broke ranks. "This country has had enough. People are tired of hearing 'wait a couple of more years' from a few huge international oil companies with enormous financial interests in conventional oil reserves located overseas," he said.

The arguments run on, but proponents inevitably come back to this point; after six years of debate the U.S. still does not have one commercial-scale synfuel plant in operation. Worse, the Energy Department and its predecessor agency seem to have spent billions of dollars without any hard results.

Moreover, synfuel proponents in Congress argue, the oil companies are always saying they need a higher price. In 1972, for example, the joint industry-government National Petroleum Council said that at $7.29 a barrel the industry could produce oil from coal or shale.

Yet today oil is selling at nearly $30 a barrel and the American Natural Resources Co. proposal to build a massive coal gasification plant in Mercer, N.D., approved yesterday by the Federal Energy Regulatory Commission, is the only large commercial plant in sight.

Jackson and other synfuels boosters, such as Sen. Mark Hatfield (R-Ore.) say, "Big oil apparently wants synfuels all to themselves, and in their own good time . . . Big oil is just plain greedy."

There is little question of the synfuel potential. An estimated 700 billion barrels -- four times Saudi Arabis's oil reserves -- is locked in oil shale deposits in Colorado. Utah, and Wyoming. And hundreds of billions barrels more can be squeezed from the country's massive coal deposits.

The coalition of opponents see it differently.

Senate Banking Committee Chairman William Proxmire (D-Wis.) is adamantly against big government synfuel spending. He says, "We tried that approach of federal force-feeding our cities . . . and the cities are worse off now than they were before we sent the money." Proxmire offered a modest synfuels bill quietly backed by Exxon and other major oil companies that would have authorized $3 billion in loan guarantees. It was defeated handily.

Many leaders in Colorado, Wyoming, Montana, and Utah -- states that would host the synfuels industry -- also oppose the administration-Jackson legislation.

"A crash program," says Sen. Willilam Armstrong (R-Colo.), "is one of the fears that has long haunted Coloradoans who are afraid the federal government will bulldoze through a program that screws up our environment."

As for the five-member quasi-public Synthetic Fuels Corp. board that would run the envisioned $88 billion program, Armstrong says, "I don't want to hand over constitutional responsibilities to an non-elected autonomous body" like that.

The scale of the plants envisioned by the Energy Department and by oil companies that expect to build them is indeed intimidating.

The SASOL II plant nearing completion in South Africa, for example, will consume 40,000 tons of coal a day to produce 58,000 barrels of diesel, gasoline, and jet fuel. During construction the on-site work force reached 20,000, handling more than 2 million pipe fittings, and 40,000 truck loads of concrete. When completed, SASOL II will be the largest commercial synfuels plant in the world.

It would take 10 such plants which cost $7 billion each to meet just a quarter of this nation's daily oil needs.

Mining, refining, and industrial operations on this scale have long raised anxieties among environmentalists.

Friends of the Earth lobbyist Dave Masselli says, "The synfuels program is Nixon's Project Independence all over again." Masselli and Gus Speth, a member of the president's Council on Environmental Quality, voiced fears that a synfuels program could severely affect the western environment.

For the plants envisioned in President Carter's program, Speth says, "About 600 square miles would have to be stripmined over the 30-year lifetime of the coal plants . . . and another 200 square miles would be required for mining oil shale."

Reclamation of the mined land would be difficult in the arid, water-short western states. And water pollutin from the chemical processes is said to pose an even more difficult problem.

Another prickly question is raised by Rep. Stockman, who wonders whether "instead of a great synfuels crusade, you will have a middle-sized pork barrel."

Stockman and other congressional opponents say research and development funding for energy is second only to that for defense and those in Congress know it. "Energy always offers a good opportunity to carry a piece of pork home," said one.

The pork barrel argument is seen partly as a struggle between East and West. Eastern coal state delegations led by Senate Majority Leader Robert Byrd (D-W.Va.) and Sen. Wendell Ford (D-Ky.) have had the edge in winning experimental coal synfuels projects for the folks at home, but the oil companies have always planned on building most commercial plants in the West.

"Eastern coal is the wrong kind," Masselli argues. "Almost all these synfuels processes work better with noncaking western coal. Besides, most eastern mines can't keep up with the 10,000 tons daily needed by big coal synfuels plants," Masselli says.

"The eastern states see the promised land out there but it is receding. If these projects are steered by the market, they will go west," Masselli predicts.

One of the hardest fought issues in the synfuels debate is GOCOs -- provisions for the Synthetic Fuels Corp. to form "government-owned, contractor-operated" synfuels companies.

The major oil companies' primary lobbying arm, the American Petroleum Institute, has vigorously opposed GOCOs. Such enterprises, they argue, pave the way for government oil and gas companies to encroach on the free market.

Jackson and Johnston say GOCOs would be formed only as "a last resort" to test new technologies the private companies consider too risky. Both say that threat of GOCOs also offers the only real level for the SFC in negotiating its contracts with the private companies.

Domenici argues that opposition to GOCOs is "an effort to once again kill the beginning of a long overdue federal effort to encourage development of synthetic fuels."

As Congress rushes to final judgment on all these questions, Milt Russell, economist with Resources for the Future, offers a wry observation: "Too many people appear to be jumping on the bandwagon without thinking about the tune they actually want the bandwagon to end up playing."