Earmarks allow lawmakers to fund projects fast, with little public scrutiny. These days, their use is mushrooming. Congressional leaders are using them to help vulnerable junior colleagues curry favor with home-state constituents to boost re-election efforts. Earmarks grease the skids for important legislation — bills loaded with spending provisions that benefit numerous congressional districts tend to garner more votes. In recent years, Republican leaders have offered lessons for newly elected lawmakers in how to get earmarks.

In the 1980s, President Reagan vetoed a transportation authorization bill because it contained a few hundred earmarks. Last year’s version included more than 6,000, including $223 million for a bridge to a sparsely populated Alaskan island — the oft-mocked "Bridge to Nowhere." In the fiscal year ended Sept. 30, 2005, there were 15,818 earmarks in all federal spending bills, up from about 3,034 in fiscal 1996, according to the research arm of Congress, the Congressional Research Service.

Earmarks made up about $40.8 billion, or 4%, of the roughly $1 trillion that Congress allocated in the 2005 fiscal year. Federal prosecutors in Washington, Los Angeles and San Diego are looking into potential abuses, including whether lawmakers have added earmarks to benefit political contributors, former staffers and friendly lobbyists. At least four congressmen, including Rep. Jerry Lewis, the current chairman of the House Appropriations Committee, are being investigated for their roles in earmarking or their ties to lobbyists specializing in earmarks.