The bill, which overwhelmingly passed the House on Monday and had already cleared the Senate, would allow individuals who perceive a threat to use force, even lethal force, in places beyond their homes, including their cars and businesses.
Pennsylvania law, like that of New Jersey and most other states, already establishes that a person has a right to defend himself in his home.
In at least two dozen states, however, the law goes further, removing a person's "duty to retreat" - say, to rush inside and bolt the door - before using deadly force.
The measure, part of an otherwise noncontroversial bill that would close loopholes in the state Megan's Law, reached Rendell's desk Friday, tripping a 10-day clock for him to act on it.
He has not announced whether he will sign or veto the bill. Rendell, a former Philadelphia district attorney, did say he thought the measure was an "unnecessary solution for something that is not a problem."
In Pennsylvania, similar proposals have been kicked around for several years, supported by the National Rifle Association. The NRA has backed such bills in other states as well.
As the latest bill gained momentum in Harrisburg this year, several law enforcement groups lined up against it - the Pennsylvania District Attorneys Association, the Pennsylvania State Police, and dozens of police chiefs from across the state.
Proponents of the expanded castle doctrine, such as the bill's sponsor, Rep. Scott Perry (R., York), said it was a matter of basic self-defense.
"If you have a legal right to be there, you should have a legal right to defend yourself," said Perry, an Iraq war veteran. "Right now, you are more valuable in your home than your driveway."
He said he had heard of law-abiding citizens who had to "fend off the D.A. and fend off a civil trial" after defending themselves from attack.
