A prospective third-party candidate is being challenged over whether his name should appear on the ballot for the state House of Representatives' 11th District.

The challenge, filed last week by two Butler County residents, claims signatures on nominating papers of would-be Constitution Party candidate Mike Rock are invalid.

A hearing in Commonwealth Court to consider the challenge is scheduled Aug. 31 in Harrisburg.

Rock of Butler Township is hoping to challenge Republican Brian Ellis and Democrat Fred Vero, both of Butler Township, in the Nov. 2 election for the 11th District seat.

The district includes Butler; Buffalo, Butler, Clearfield, Donegal, Oakland, Summit, Winfield and Connoquenessing townships; and Chicora and East Butler boroughs.

The House seat is being vacated at the end of the year by Democratic state Rep. Guy Travaglio, who opted not to seek re-election to a sixth term.

The lawsuit filed Aug. 9 by Gregory Furer and Larry Thompson, both Republican committeemen in the county, claims more than 130 signatures on Rock's nominating papers should be disqualified.

By law, Rock needed 300 valid signatures to appear on the November ballot. His papers submitted to the Department of State included 381 signatures.

The suit claims that 99 signatures were from individuals not registered to vote, and therefore should be disqualified.

Additionally, the suit alleges that 31 signatures are invalid because they were from individuals who do not live in the 11th District.

Five others signatures are not legible and another was from an individual who signed Rock's nominating papers twice, and should be stricken, according to the suit.

The suit also notes that 260 signatures were on nominating papers circulated by Hagan Smith of Penn Township, an officer for Butler County's chapter of the Constitution Party.

The signatures should be thrown out since Smith does not live in the 11th District, the suit contends.

However, according to state law, circulators of nominating papers for state office do not have to live within the legislative district for which the candidate is seeking office.

Rock did not return a telephone message left at his home Monday.

Among those subpoenaed to testify at the Aug. 31 hearing is Regis Young, director of the Butler County Election Bureau.

Young has been called to testify of the identities of those whose signatures have been challenged, including their addresses and their registration status.

Rock in 2000 as the Republican nominee challenged Travaglio in the 11th District. Travaglio defeated Rock by a vote of 16,030 to 7,692, or 68 percent to 32 percent.

Rock since changed his registration to the Constitution Party - a party that claims 12 voters in Butler County.

The Constitution Party grew out of the U.S. Taxpayers Party, which was formed by a coalition of independent parties in 1992. In the 2000 elections, the Constitution Party was on the presidential ballot in 41 states.

The national party's Web site says its mission is to secure liberty by electing candidates at all levels of government who will uphold the principles of the Declaration of Independence and the U.S. Constitution.

"It is our goal to limit the federal government to its delegated, enumerated, Constitutional functions and to restore American jurisprudence to its original Biblical common-law foundations," according to the Internet site.

"The Constitution Party is the only party which is completely pro-life, anti-homosexual rights, pro-American sovereignty, anti-globalist, anti-free trade, anti-deindustrialization, anti-unchecked immigration, pro-second amendment, and against the constantly increasing expansion of unlawful police laws, in favor of a strong national defense and opposed to unconstitutional interventionism," the Web site says.