David Nolan, who helped found the Libertarian Party in his Denver home and watched it grow into a force with national influence, died unexpectedly Sunday. The Tucson resident was 66.

Nolan, whose friends described him as a "guiding light" of the Libertarian Party, opposed expansive government and had pledged to abolish personal income taxes if elected to office.

In 2006, Nolan unsuccessfully ran against Gabrielle Giffords for a seat in Arizona's 8th Congressional District.

This year, he challenged John McCain for his Senate seat and racked up 63,000 votes - in a state with only 24,000 registered Libertarians.

"Dave was kind of a unique character," said Jack Dean, a longtime friend and political ally of Nolan's. "The Libertarian Party was literally founded in his living room in Denver."

Dean said Nolan remained a constant force in the Libertarian Party as it grew.

"He was sort of a guiding light," Dean said. "He was kind of our conscience. Dave was a presence at every national convention; everyone respected him. He kept reminding everybody what the goal was."

Dean described Nolan as a "platform kind of person, keeping the party on track."

Nolan also is the namesake for what is called the "Nolan Chart" - a graphic representation that shows where Libertarians stand in relation to liberals, conservatives and other political identities.

"He was a low-key and extremely reasonable radical," Dean said. "And he could make Libertarian positions sound reasonable and logical to anyone."

Among other things, Nolan supported immigration-law changes along the lines of a guest-worker program. Like other Libertarians, Nolan called for the legalization of drugs, saying that the illegal trade in drugs is what fuels cartels, and he opposed the war in Iraq.

This year, during a September debate with McCain and other Senate candidates, Nolan remained true to Libertarian ideals of personal freedom and less government. When candidates were asked about a border wall, he replied:

"Americans should always remember: Big walls are often used to keep people in as well as out. If America ever turns fascist, we don't want to be in a big, giant prison."

Nolan's cause of death was unclear late Sunday, and no information was immediately available on memorial services.

He is survived by his wife, Elizabeth.

Contact reporter Clayton R. Norman at 573-4115 or cnorman@azstarnet.com