The Supreme Court on Thursday is scheduled to consider whether it will revisit constitutional Speech or Debate Clause protections under an appeal from ex-Rep. William Jefferson (D-La.).

The court could announce as early as Monday whether it will accept the case for its 2009-2010 session, which begins in October. Alternately, the court could delay its Thursday discussion of the case — although it would not cite a specific reason — and reschedule its conference for a later date.

Should the Supreme Court decide to take up the case, it would all but certainly have an impact on Speech or Debate protections and could affect future indictments against Members of Congress, or even establish new precedents for submitting evidence to grand juries.

“The Jefferson case is like a legal hurricane that spins off tornadoes of novel issues,— said Jonathan Turley, a professor at George Washington University Law School.

But the Supreme Court accepts only a minute number of the more than 10,000 cases listed on its docket each term, and legal experts suggested Tuesday that Jefferson is unlikely to be chosen.

“The odds are heavily against Jefferson in accepting the case,— said Turley, who does not represent either the government nor Jefferson. “If the court turns down the case, it would very likely be with little or no discussion.—

Attorneys for the former Louisiana lawmaker assert in court documents that the Justice Department violated the Constitution’s Speech or Debate Clause when prosecutors provided a grand jury with evidence of Jefferson’s legislative activities in order to obtain an indictment in 2007.

Jefferson is charged with 16 counts of violating federal law for allegedly offering and accepting hundreds of thousands of dollars in bribes to promote business ventures in West African nations. He is seeking the dismissal of the corruption charges.

The defense has challenged grand jury testimony by former Jefferson aides who described the lawmaker’s role in the passage of a trade bill benefiting countries in Africa, among other legislative activities.

“The Speech and Debate Clause does not prevent the government from inquiring into the actions of the Congressman,— Turley said. “It would be ridiculous to say you could not question staffers on some aspects of legislation in a bribery case. But it’s a very delicate line.—

“It would have been much easier a task if they had not raided his office,— Turley added in reference to a 2006 FBI raid on Jefferson’s Congressional office in the Rayburn House Office Building.

In March 2008, the Supreme Court denied an appeal from the Justice Department seeking to overturn a lower court ruling that the raid had violated the Speech or Debate Clause.

The U.S. Circuit Court of Appeals for the District of Columbia had earlier ruled that the raid violated Jefferson’s rights because the FBI seized items from his Congressional office without allowing him to assert privilege over any legislative materials.

In Jefferson’s petition to the Supreme Court, lead defense attorney Robert Trout wrote: “Mr. Jefferson maintains his innocence and will defend against all of the charges in the indictment at trial.—

He continued: “More importantly for purposes of this petition, he — like all current and former Members of Congress — has an absolute constitutional right not to stand trial at all on charges obtained in violation of the Speech or Debate Clause.—

In documents filed by the Justice Department opposing the petition, prosecutors refute that argument, asserting that the aides’ testimonies is permissible.

“The purpose of the Speech or Debate Clause is to ensure that Members of Congress can perform their legislative duties without fear that they will be sued or prosecuted for them,— the Justice Department wrote in court documents. “The Speech or Debate Clause does not purport to confer a general exemption upon Members of Congress from liability or process in criminal cases.’ … Rather, it protects only those activities that are an integral part of the deliberative and communicative processes by which Members participate’ in their constitutionally-mandated duties.—

Melanie Sloan, executive director of the watchdog group Citizens for Responsibility and Ethics in Washington and a former assistant U.S. attorney, predicted the court is unlikely to accept the appeal because Jefferson does not demonstrate a stark contrast in circuit court decisions on Speech or Debate protections.

“The Supreme Court generally likes to hear conflicts between the circuits,— Sloan said.

In its November 2008 decision, the U.S. Court of Appeals for the Fourth Circuit rejected Jefferson’s appeal but did not rule directly on whether Speech or Debate violations existed, stating it was “barred … from looking behind an indictment to assess whether the grand jury had considered privileged legislative materials.—

In court documents, Jefferson’s defense team argued that appellate courts for the District of Columbia and the Third and Eleventh circuits have ruled otherwise. “Those circuits concluded that a court has the power to examine the evidence presented to a grand jury to determine whether the Speech or Debate Clause has been violated, and to dismiss the indictment where a violation is found,— Trout wrote.

Jefferson’s trial is scheduled to begin June 2 in the U.S. District Court for the Eastern District of Virginia.