Long time Sen. Arlen Specter died Sunday morning after a battle with non-Hodgkin lymphoma.
The 82-year-old represented Pennsylvania in the U.S. Senate for 30 years.
Specter started and ended his political career as a Democrat, but he spent most of his career in-between as a Republican.
He was finally ousted from office after he voted for President Obama's stimulus package in 2009 and switched to the Democratic party.
Specter played a key role in many Supreme Court nominations, helping to block conservative candidate Robert Bork. He also helped put Justice Clarence Thomas on the court.
Many remember him as the longest serving senator in Pennsylvania history. Duquesne University law professor Ken Gormley said Specter is an icon in the state.
"He started as a young lawyer working for the Warren Commission after President Kennedy was assassinated," Gormley said.
"(He) became a senator at a young age and we remember as a kid, he would be down in the stands at Three Rivers Stadium at Steelers games introducing himself, just getting to know, he wanted to know the whole stadium," he said.
A public funeral for Specter will be held Tuesday in Pennsylvania.