DeMint Earmark Press Conference (Photo by AFP)

A bipartisan effort to put a one-year freeze on earmarks has attracted the support of at least 14 senators, including each party’s presidential contenders, setting the stage for a showdown Thursday over wasteful government spending. Despite the surge in support over the past 24 hours, however, Senate Democrat leaders are threatening to derail the plan.

Majority Leader Harry Reid (D-Nev.), Whip Dick Durbin (D-Ill.) and Budget Chairman Kent Conrad (D-N.D.) have vowed to stand in the way of the amendment, sponsored by Sens. Jim DeMint (R.-S.C.) and John McCain (R-Ariz.). Even with the backing of Sens. Hillary Clinton (D-N.Y.) and Barack Obama (D-Ill.), the measure could run into opposition from big spenders in both parties. Durbin told Congressional Quarterly today:

When it comes to projects around my state and the rest of the nation I don’t think it’s unreasonable for Congress to have some input in that discussion.

Conrad has indicated he is working on an alternative to the DeMint-McCain amendment. However, it would emphasize transparency but keep the earmark favor factory open for business — giving its supporters cover if they vote against the DeMint-McCain amendment.

Most Republican leaders — aside from Sens. Jon Kyl (R-Ariz.) and John Cornyn (R-Tex.) — have remained silent or uncommitted to the DeMint-McCain plan. Asked about the amendment today, Minority Leader Mitch McConnell declared, “Frankly, I’m not certain what the outcome will be. And I haven’t decided, personally, how I’m going to vote on that yet.”

The uncertainty isn’t slowing DeMint. He joined several members of Congress at a Capitol Hill press conference today to outline his rationale for the amendment. He acknowledged the procedural hurdles he and his colleagues will face, particularly the 60-vote threshold that could be hard to overcome.

Even though appropriators on Capitol Hill may not be ready to give up their addiction to pork, public support for ending earmarks appears to be reaching an all-time high. The organization presented DeMint with petitions signed by more than 107,000 people. On his own website, DeMint has collected about 40,000 signatures.

Several taxpayer watchdog groups, including National Taxpayers Union, Americans for Prosperity, Citizens Against Government Waste, FreedomWorks and Americans for Tax Reform, have also lined up behind the effort.