The justices, without comment, refused to disturb lower court rulings dismissing Public Citizen's lawsuit contesting the validity of a $39 billion deficit-reduction bill that passed the House and Senate in slightly differing versions.

The controversy arose in February 2006 after the House passed a version of the bill that was not identical to the Senate-passed measure. Both houses of Congress were under Republican control at the time.

Ordinarily, one chamber would vote again to eliminate the discrepancy. But the vote in the House was 216-214, too close to risk another vote.

Republicans who were in charge in the House refused Democrats' demands for a new vote. Instead, Republican leaders in the House and Senate signed off on the legislation and sent it to President Bush, who signed it into law on Feb. 8.

The provision at issue involved how long Medicare pays for renting some types of durable medical equipment. The Senate voted for 13 months, as intended by Senate and House negotiators, but a Senate clerk erroneously put down 36 months in sending the bill back to House for a final vote. That's what the House approved Feb. 1.

By the time the bill was shipped to Bush, the number was back to 13 months as passed by the Senate.

Lower courts dismissed Public Citizen's lawsuit based upon a 1890 case in which the court held that judges are obliged to accept as accurate legislation that has been signed by the leaders of both houses of Congress. An occasional mistake, or even fraud, is better than the uncertainty that would flow from routine questioning of bills passed by Congress, the court said then.