Federal prosecutors are urging an appeals court to get on with Rep. William Jefferson's corruption trial, saying his appeal to the Supreme Court does not have enough chance of success to justify further delays.

Jefferson. D-La., was indicted on bribery charges after agents found $90,000 in his freezer. He has pleaded not guilty and his lawyers argue that his trial should be delayed pending his appeal to the U.S. Supreme Court.

Jefferson argues that the charges are invalid because a grand jury got access to information about his actions as a member of Congress. That, Jefferson claims, runs afoul of a constitutional clause that shields members of Congress from civil or criminal action stemming from the performance of their legislative duties.

But in a brief filed this week in Richmond, Va., with the 4th U.S. Circuit Court of Appeals, prosecutor Mark Lytle said delaying the trial would cause "further prejudice," or harm, to the government's case against the nine-term congressman. The government brought the charges 18 months ago.

Jefferson, Lytle wrote, has not shown the required "reasonable probability" of success with the high court on the merits of his case.