* 1982 decree intended to stop alleged ballot box abuse
* Republicans cited free speech, voter fraud in bid to end decree (Adds paragraphs 3-9, case citation, byline)
By Jonathan Stempel
WASHINGTON, Jan 14 (Reuters) - The U.S. Supreme Court on Monday refused to hear a legal challenge by the Republican National Committee to dissolve a 1982 decree designed to stop the improper suppression of voting by particular groups.
Without comment, the court decided not to review a March 2012 ruling by a federal appeals court in Philadelphia that extended the decree to November 2017, with modifications previously made by a federal district judge.
The decree arose from a lawsuit during New Jersey's 1981 gubernatorial election, when the Democratic National Committee accused the RNC of trying to intimidate minority voters through so-called "ballot security" measures.
These measures included the creation of voter challenge lists, and the posting of off-duty sheriffs and police officers, some of whom were armed, at polls in minority precincts, according to the DNC.
Under the decree, which later became national in scope, the RNC needs court approval to implement various poll-monitoring activities in minority precincts.
The RNC sued in November 2008 to void the agreement, citing a rise in voter fraud, changes in federal and state election laws, its good-faith compliance with the decree, and free speech rights.
But the 3rd U.S. Circuit Court of Appeals in Philadelphia rejected the request, saying the RNC had not identified any significant changes that would make it unfair to continue the decree.
In its appeal to the Supreme Court, the RNC said the 3rd Circuit improperly relied on prior case law and a federal civil procedure role to expand and extend the decree.
The DNC had urged the 3rd Circuit decision to let the decree stand, saying the lower courts were not divided on the issue, and that the appeals court had not abused its discretion in this case.
The case is Republican National Committee v. Democratic National Committee, U.S. Supreme Court, No. 12-373. (Reporting by Jonathan Stempel; Editing by Paul Simao)