The Pennsylvania Supreme Court today overturned a lower court's ruling that said Westmoreland County must hold a referendum before purchasing electronic voting machines.

The order now clears the way for two dozen counties, including Allegheny and Westmoreland, to replace their aging lever machines, a requirement of the federal Help America Vote Act.

Under the federal law, known as HAVA, local governments nationwide must upgrade their voting equipment this year. Pennsylvania counties face a deadline of the May 16 primary election to comply with HAVA, or they risk losing millions in federal aid.

Officials in Westmoreland County had planned to buy more than 700 touch-screen machines from Elections Systems and Software Inc. at a cost of $2 million. But a group of voting activists, including state Sen. Jim Ferlo, D-Highland Park, sued to block the purchase, citing a provision in the state Constitution that calls for referendums before counties shift to new voting technologies.

Last month, Commonwealth Court Judge Dan Pellegrini ruled in favor of the activists and ordered the county to use paper ballots for federal elections until a referendum could be held. The county could continue to use lever machines for state and local elections.

Both sides argued before the Supreme Court yesterday, with a lawyer for the state warning that Judge Pellegrini's order could cause election day chaos in Pennsylvania that would rival Florida's problems during the 2000 presidential election. The lawyer, Mark Aronchick of Philadelphia, also argued that HAVA takes precedence over the state's referendum requirement.

The high court's decision today invalidates Judge Pellegrini's order. The court has not yet issued an opinion in the case.

The ruling also should reduce the likelihood of a federal lawsuit against Pennsylvania and Westmoreland County. Last week, the Justice Department threatened such action if the county and the state failed to move on voting machine purchases.

The federal government this week sued New York State because officials there have been slow to comply with HAVA.