WASHINGTON -- Sens. John McCain and Tom Coburn may force their colleagues to make an up-or-down public decision on proposals such as tucking $2 million for a public park in San Francisco into the nation's massive military spending bill. Last Dec. 20, this bit of pork was passed by Congress without debate and without a vote in the final version of the Defense Appropriations Act.

McCain and Coburn last Wednesday proposed a revolutionary change in the way Congress has done more and more of its business over the past two decades. They announced their intention to "challenge" future earmarks as a violation of Senate rules. That would have meant a roll call vote on each of the 15,268 special spending items in 2005 (nearly a four-fold increase over the previous decade) that individual members quietly slipped into massive bills in the dead of night.

McCain, a lonely voice in the Senate battling the bipartisan taste for pork, was joined last year by newly elected Dr. Tom Coburn, the flinty obstetrician from Muskogee, Okla. Even their combined voices probably would not have been heard were it not for the Jack Abramoff lobbyist scandal. Now, the demand for pork by politicians that consumed $27 billion last year could be endangered.

Make no mistake that Republicans McCain and Coburn are climbing uphill against a bipartisan pork coalition, as was made clear from both sides of the aisle this week. "Who knows best where to put a bridge or a highway or a red light in their district?" said House Speaker Dennis Hastert, defending earmarks on the Michael Reagan radio program. Senate Democratic Leader Harry Reid said on PBS: "There's nothing basically wrong with the earmarks. They've been going on since we were a country."

Coburn disputes Reid's history. "Contrary to conventional Beltway wisdom," the freshman senator said, "the pork process is not an ancient tradition that is impossible to change." The 1982 highway bill contained 10 earmarked pork projects; 150 earmarks in the 1987 bill helped provoke a veto by President Reagan; the number rose to 1,400 in 1998, and to 6,300 in 2005.

In an age of polarization, addiction to pork cuts across party lines. The $2 million for a public park in the Presidio of San Francisco added to Defense spending benefits the district of House Democratic Leader Nancy Pelosi, a leading attacker of Republican fiscal irresponsibility.

McCain took the floor last Dec. 20, as he has so many times in the past, with an inattentive Senate prepared to pass a $458 billion Defense Appropriations Bill, including funds for the war in Iraq. "During a war, in a measure designed to give our fighting men and women the funds they need," said McCain, "the Congress has given in to its worst pork-barrel instincts." These were among the earmarks he pointed out:

 -- $3,850,000 for the Intrepid Sea-Air-Space Foundation at Manhattan's Pier 86 on West 46th Street in New York City. The district is represented by liberal Democratic Rep. Carolyn Maloney.

 -- $4.4 million for a technology center at Missouri State University in Springfield, Mo. This was included in $27.1 million earmarked for Southwest Missouri in this one bill by Acting House Majority Leader Roy Blunt, who is running for the permanent leadership post.

 -- $500,000 for an outdoor grade-school teaching project ("Summer Science and Adventure Camp") in Boswell, Pa. The district is represented by Democratic Rep. John Murtha, who has become a leading critic of President Bush's Iraq policy.

 -- $500,000 for the Arctic Winter Games, an international sports competition on the Kenai Peninsula in Alaska. Sen. Ted Stevens, president pro tem of the Senate and chairman of the Defense Appropriations Subcommittee, determined this was a fitting expenditure for a military supply bill.

These are just samples of what McCain and Coburn want to force their colleagues to approve or disapprove. The other senators will hate that ordeal, but neither McCain in his four-term Senate career nor Coburn in his previous six years in the House has ever wanted to win a popularity contest. They can tell the other senators that if they want to avoid the embarrassment of voting on pork, they can stop earmarking.