Sen. Barack Obama and Senate Majority Whip Dick Durbin rarely disagree on policy matters, but the two Illinois Democrats have staked out opposite ends of the contentious debate over congressional earmarks.

Obama has embraced an idea proposed by one of the most conservative members of the Senate, sharing the desire for a moratorium on the local spending projects. Durbin is “disappointed” in his fellow Illinois Democrat, despite being Obama’s biggest Senate supporter in the presidential race.

To be sure, Sen. Hillary Rodham Clinton (D) and her New York Senate colleague, Charles Schumer (D), are also split on the issue. Clinton has lined up with Obama to support it, while Schumer is opposed.

DeMint’s idea — a one-year “time-out” from earmark appropriations — was a particularly hot topic during Tuesday’s partisan policy luncheons, held just hours after DeMint held a press conference outside the Capitol that featured a supporter in a 6-foot-tall pink pig suit.

Democratic leaders used their luncheon to urge their members to oppose the DeMint amendment, although Durbin acknowledged that Clinton’s and Obama’s support makes that difficult.

In private meetings, when some members of the Democratic Conference questioned whether they should oppose their presidential candidates, Durbin said he replied, “Well, they could be wrong, too.”

Democrats said they are considering drafting an alternative amendment that would propose ways to “tighten up” the earmarking process. Durbin said some ideas were “tossed around” during Tuesday’s policy luncheon.

Durbin and other Democratic leaders — as well as many Republicans — have instead suggested increasing the transparency of earmarks, arguing that many of them have merit and Congress has a duty to dole out federal funds.

Obama announced his position in a statement on Monday that criticized the current earmark process as “broken,” even with increased transparency and accountability, and said that DeMint’s amendment represents the best chance at reform.

“The entire earmarks process needs to be re-examined and reformed,” Obama said.

DeMint acknowledged that his position rankles members of his party.

“I tried two years of sweet-talking, and that didn’t work,” he said. “I’m a recovering earmarker myself. But then I saw someone get $100,000 for a project in South Carolina and $300 million for a bridge in Alaska. And they expect you to vote for the bill. It’s an internal extortion racket.”

Senate Budget Committee Chairman Kent Conrad (D-N.D.) also repeated on Tuesday his opposition to DeMint’s amendment because earmarks help even out the process. Rural states, he said, traditionally receive less money from federal agencies because those agencies are led by officials from more heavily populated areas. If Congress gives up its input in funding decisions, Conrad said, those federal officials will have complete control.

“Earmarks by another name are congressionally directed funding,” he said.

DeMint’s divisive proposal is also close to uniting Senate Majority Leader Harry Reid (D-Nev.) Minority Leader Mitch McConnell (R-Ky.). Reid said Democrats have already taken “sweeping” steps toward increasing transparency over earmarks, and noted that President Bush’s own budget contains numerous earmarks that reflect his own priorities.

“If people think there is some way we can improve [transparency], let them do that,” he said. “But to just carte-blanche say, ‘No more earmarks’ is unrealistic. There are a lot of presidential earmarks.”

McConnell, who appointed a five-member task force in January to study the situation surrounding earmarks, said Tuesday he is waiting until the task force issues a recommendation. In the past, however, he has been a top appropriator for Kentucky and has been skeptical of calls to rein in the practice.

In a sign of the heating rhetoric surrounding the issue, however, Missouri Republican Kit Bond had a one-word description of DeMint’s proposal: “Stupid.”

Fellow Republican Tom Coburn of Oklahoma, a supporter of the amendment, shot back that senators are ignoring the issue at their political peril.

“Anybody who stands against earmark reform is going to find themselves back home,” he said.

Manu Raju contributed to this article.