On CBS' "Face the Nation," Rendell joined a chorus of voices calling for toned-down political rhetoric in the face of last Saturday's shootings, in which six were killed and 13 wounded when 22-year-old Jared Lee Loughner allegedly opened fire at a political event outside of a Tucson grocery store.
Among the injured was Arizona congresswoman Gabrielle Giffords, who sustained a bullet wound to the head and currently remains in critical condition.
Complete Coverage: Tragedy in Tucson
Rendell emphasized the increasingly heated nature of political discourse in recent months, and urged Congress to take the tragedy as an opportunity to change its tone.
"In my eight years I've seen the level of partisanship and ideological posturing just increase and increase and increase, and I think it's tearing the fabric of our government apart," the outgoing Democratic governor told CBS' Bob Schieffer. "If these lives were lost for a reason, the reason is if we can take something good out of it. This is a wake-up call to all of us, that we can't go on the way we're doing.
"If that happens, this tragic day will have done some real good," Rendell continued.
Arizona Republican Rep. Jeff Flake said he thought Congress would see "a more civil debate" in the wake of the shootings, but conceded that the real difficulty would be maintaining that tone in the future.
"I think that we Republicans, and I think Democrats alike, will realize that if we tone down the rhetoric sometimes our debate is more effective from our own side," Flake said.
But he added that "it's easy to slip back into old ways ... Keeping that into the future is going to be a tough thing."
Former New York City Mayor Rudy Giuliani decried what he described as "a rush to judgment on both sides" in the wake of the shootings: "Left wingers trying to blame it on right wing Tea Party, Sarah Palin. Right wingers trying to fight back and defend themselves against what was really an outrageous charge," he told Schieffer.
"The reality is that that settled pretty quickly when we learned the history. And I thought the President's speech put it on a different tone," Giuliani told Schieffer.
"I think we have a chance to do the same thing that we did after September 11," he said.
In a call for increased bipartisanship, some members of Congress have proposed that both parties sit together at President Obama's State of the Union address, which will take place on January 25.
"It's a symbol," said Democratic New York Sen. Kirsten Gillibrand, one of the champions of the plan. "You'll create an image of the Congress deciding that we are going to work as a body, not as two separate sides. That's a very good place to start."