Niagara Gazette — HARRISBURG, Pa. — Former U.S. Sen. Arlen Specter, the outspoken Pennsylvania centrist whose switch from Republican to Democrat ended a 30-year career in which he played a pivotal role in several Supreme Court nominations, died Sunday. He was 82.

Specter, who announced in late August that he was battling cancer, died at his home in Philadelphia from complications of non-Hodgkin lymphoma, said his son Shanin. Over the years, Arlen Specter had fought two previous bouts with Hodgkin lymphoma, overcome a brain tumor and survived cardiac arrest following bypass surgery.

Specter rose to prominence in the 1960s as an aggressive Philadelphia prosecutor and as an assistant counsel to the Warren Commission, developing the single-bullet theory that posited just one bullet struck both President Kennedy and Texas Gov. John Connally — an assumption critical to the argument that presidential assassin Lee Harvey Oswald acted alone. The theory remains controversial and was the focus of Oliver Stone's 1991 movie "JFK."

In 1987, Specter helped thwart the Supreme Court nomination of former federal appeals Judge Robert H. Bork — earning him conservative enemies who still bitterly refer to such rejections as being "borked."

But four years later, Specter was criticized by liberals for his tough questioning of Anita Hill at Clarence Thomas' Supreme Court nomination hearings and for accusing her of committing "flat-out perjury." The nationally televised interrogation incensed women's groups and nearly cost him his seat in 1992.

Specter was Pennsylvania's longest-serving senator when Democrats picked then-U.S. Rep. Joe Sestak over him in the 2010 primary, despite Specter's endorsements by President Barack Obama and other Democratic leaders. Sestak lost Specter's seat to conservative Republican Rep. Pat Toomey by 2 percentage points.

A political moderate, Specter was swept into the Senate in the Reagan landslide of 1980.

He took credit for helping to defeat President Clinton's national health care plan — the complexities of which he highlighted in a gigantic chart that hung on his office wall for years afterward — and helped lead the investigation into Gulf War syndrome, the name given to a collection of symptoms experienced by veterans of the war that include fatigue, memory loss, pain and difficulty sleeping. Following the Iran-Contra scandal, he pushed legislation that created the inspectors general of the CIA.

As a senior member of the powerful Appropriations Committee, Specter pushed for increased funding for stem-cell research, breast cancer and Alzheimer's disease, and supported several labor-backed initiatives in a GOP-led Congress. He also doggedly sought federal funds for local projects in his home state.

Specter was not shy about bucking fellow Republicans.

In 1995, he launched a presidential bid, denouncing religious conservatives as the "fringe" that plays too large a role in setting the party's agenda. Specter, who was Jewish, bowed out before the first primary because of lackluster fundraising.

Despite his tireless campaigning, Specter's irascible independence caught up with him in 2004. Specter barely survived a GOP primary challenge by Toomey by 17,000 votes of more than 1.4 million cast. He went on to easily win the general election with the help of organized labor, a traditionally Democratic constituency.

Specter startled fellow senators in April 2009 when he announced he was switching to the Democratic side, saying he found himself "increasingly at odds with the Republican philosophy." Earlier in the year, he had been one of only three Republicans in Congress — and the only one facing re-election in 2010 — who voted for President Barack Obama's economic stimulus bill.

He also said he had concluded that his chance of defeating a GOP challenger in the 2010 party primary was bleak. But he said the Democrats couldn't count on him to be "an automatic 60th vote" to give the party a filibuster-proof majority.

Specter outspent Sestak, a retired Navy vice admiral, but Sestak attacked him as a political opportunist who switched parties to save his job. A memorable campaign ad used Specter's own words against him: "My change in party will enable me to be re-elected."

Specter was diagnosed in 2005 with stage IV Hodgkin lymphoma, a cancer of the lymphatic system. Announcing the diagnosis with his trademark doggedness, Specter said: "I have beaten a brain tumor, bypass heart surgery and many tough political opponents and I'm going to beat this, too."

"Arlen Specter was always a fighter," Obama said in a statement Sunday. "From his days stamping out corruption as a prosecutor in Philadelphia to his three decades of service in the Senate, Arlen was fiercely independent — never putting party or ideology ahead of the people he was chosen to serve. He brought that same toughness and determination to his personal struggles."