Santorum said that change in perspective was the greatest gift from his defeat, from a political point of view, and it helped him see the conservative frustration that he had heard while in office.
"It didn't quite resonate with me. You're in there sort of doing the sausage-making and it's like, 'Well they don't understand,' and in a sense, I didn't understand," he said at the Pennsylvania Leadership Conference, the state's largest annual gathering of conservatives.
Santorum is trailing front-runner Mitt Romney in the GOP presidential race. He reiterated his criticism that Romney's beliefs are too similar to President Barack Obama's to attack the Democrat on the key issues of health care and the economy.
Asked after his speech by a reporter about pressure to bow out of the race, Santorum responded, "What pressure?"
There's still resentment among key Pennsylvania conservatives over some of Santorum's positions on fiscal issues while he was in the Senate and his enthusiastic support for moderate Sen. Arlen Specter in the 2004 GOP primary over conservative favorite Pat Toomey.
Some other Pennsylvania Republicans worry that Santorum's blunt talk on social issues may repel the moderates and independents who are crucial to winning statewide elections in the diverse state. Many of the state's top party officials, including Gov. Tom Corbett, Lt. Gov. Jim Cawley and state party chairman Rob Gleason, remain publicly uncommitted in the presidential race. Toomey, who won Specter's seat in 2010, also is uncommitted in the race.
On Saturday, Santorum did not refer to any specific criticism by conservatives, or disagreement he may have had. Before his 2006 defeat by Democrat Bob Casey, Santorum was the No. 3 Republican in the U.S. Senate.
Party nominees are usually unofficially settled by the time Pennsylvania's primary rolls around, but this year it could play a part. The statewide April 24 election does not automatically deliver votes to the winner, since all 72 convention delegates are free to support whoever they want.