The hold and blue slip: Who needs a filibuster?

Unlike filibusters, the mechanisms related to blue slips and holds are not spelled out in the Senate rulebook. Instead, they owe their existence to powerful traditions of senatorial courtesy and the ability of a single lawmaker to gum up the works.

The blue slip refers to the piece of paper by which senators provide input to the Judiciary Committee chairman on nominees from their respective states.

While a negative response has always been bad news for a nominee's fortunes, the question nowadays is whether it should constitute an outright veto.

That was true from 1956 to 1978 when the late Sen. James Eastland, D-Miss., ran the Judiciary Committee. The panel's chairmen have since tended to be more flexible, although continuing to give substantial weight to a negative blue slip. Among them were Sens. Ted Kennedy, D-Mass., and Joseph Biden, D-Del. Nonetheless, Democrats protested strenuously when the current committee approved several Bush appellate-court nominees despite blue-slip objections from Michigan's two senators, both Democrats. Those nominees are among the 10 to run into filibusters in the full Senate.

On a daily basis, the Senate operates under a process known as "unanimous consent," by which lawmakers agree to take up bills and other matters unless someone objects. A hold, which is registered with the Senate majority leader, is essentially a threat to disrupt that flow of business with a filibuster.

Although the majority leader can always say no, he's going to want to keep his colleagues happy whenever possible, said Steven Smith, an expert in congressional procedures at Washington University in St. Louis. "He needs their cooperation; he doesn't want to alienate them."