Robert Pendleton, a longtime Nassau conservative activist who fought for changes to state election laws and once sued his own party over its leadership, died Sunday after a nine-month battle with cancer. He was 70.

"He loved his country," said Carol Pendleton, his wife of 40 years. "He always wanted to try to do the right thing."

In 2012, Pendleton, of Merrick, and two other Republican activists unsuccessfully sued the state in federal court, looking to overturn New York's requirement that candidates collect petition signatures to qualify for a spot on the ballot. The trio argued the process of gathering signatures door-to-door violated the Americans with Disabilities Act, because it was "physically demanding." They also said municipal workers could be subject to retaliation over their signatures because the petitions are public record.

"He had a tremendous amount of passion for politics," said his longtime friend Barry Del Mastro of Elmont. "His drive, his determination, it was all because he just wanted to see better government."

Pendleton and a handful of other conservative activists sued the Nassau County Conservative Party in 2011, seeking to remove the party's leadership. They argued unsuccessfully in state Supreme Court that party leaders had improperly installed a slate of candidates.

"His heart and soul was in the Conservative Party," said Pat Friedman, a longtime Elmont activist who was part of the lawsuit.

advertisement | advertise on newsday

Pendleton was born in Providence, R.I., but grew up in Brooklyn and Queens, later joining the Air Force during the Vietnam era, his wife said. She added that he also been an ironworker during the construction of the World Trade Center, before the couple started a steel refurbishment company.

An active member of the Rockville Centre tea party, Pendleton was known for his ability to "energize" members at meetings, said group co-organizer Bryan Korman.

"This was a man who knew politicians on a first-name basis," said Korman. "He really cared about the community. He cared about a quality of life for everyone on Long Island."

Funeral services are scheduled for 2 p.m. to 5 p.m. and 7 p.m. to 9 p.m. Wednesday at O'Shea Funeral Home, 603 Wantagh Ave., in Wantagh. A church service is planned for 10 a.m. Thursday at Curé of Ars Roman Catholic Church, 2323 Merrick Avenue in Merrick. He will be buried at Calverton National Cemetery.