In an interview on CBS' "Face the Nation" Sunday morning, Giuliani said that while the tragedy may provide the nation with "a real opportunity to try to have more civil discourse," he emphasized his belief that the tone of American political rhetoric wasn't the impetus for the actions of alleged gunman Jared Lee Loughner.
"The lack of civil discourse wasn't the cause of this, as some people thought," Giuliani told CBS' Bob Schieffer.
Complete Coverage: Tragedy in Tucson
"This man was crying out for someone who needed to be treated," Giuliani continued. "He was being told to be treated. People were saying he was bizarre. People were saying he was frightening. A teacher wouldn't be with him without a guard being there. Gosh, you would think at some point along the way he'd have been evaluated.
"It isn't an isolated incident: We could go back and look at lots of incidents like this where people weren't being treated," he said.
The former mayor said that after the issue of mental health care had been addressed on a national level, and American politicians were able to "reestablish a situation of civility," it then might be time to re-open the debate about gun control laws.
"There are people that would argue that if more people had guns, this may not have happened because somebody might have been able to take action immediately and stop him before he inflicted either damage or as much damage as he did," Giuliani said. "We've got a very strong debate on guns. We're going to need a level of civility to discuss it that leads to rationality."
Pennsylvania Governor Ed Rendell also called for improvements to America's mental health care system - and argued that such upgrades might help to prevent similar acts of violence in the future.
Rendell emphasized the need for early detection in America's mental health care system, so that "we can get people help," but also called for a more finely-tuned system of classifying individuals with mental health issues.
"Had this man been classified, had he been committed civilly at any time prior to his purchasing the gun from Wal-Mart, he would have in fact been denied access to that firearm," Rendell said of Loughner.
Rendell urged for "a rational discussion on guns" and the reinstitution of the Federal Assault Weapons Ban, which expired in 2004.
Rendell said the pressure of interest groups must be set aside so that society can ask: "Does any citizen protecting themselves or their home or using a handgun to hunt, do they need a clip that has 33 bullets in it?"
Rendell added, "The answer is of course not.
"I think the nation's spirits would be lifted if the Congress acted quickly with the president and reinstated the assault weapons ban which also had the ban on these large magazines, these clips that carried 30-plus bullets," he said.