Santorum has made this argument many times, as Dave Weigel points out at Slate, but the soundbite and the message convey his campaign's lesser focus on the economy.

.@RickSantorum in IL "I don't care what the unemploy rate is gonna be,its doesn't matter to me.." says he's running for bigger issue freedom
— Kelly O'Donnell (@KellyO) March 19, 2012
Santorum: I don't care what the unemployment rate is going to be. My campaign doesn't hinge on unemployment and growth rates
— Arlette Saenz (@ArletteSaenz) March 19, 2012
UPDATE: Romney in Peria, Ill. just now: "I do care about the unemployment rate, it does bother me. I want to put people back to work."
The quote as clipped by the Romney campaign:
View this video on YouTube
#economiclightweight RT @KellyO: .@RickSantorum in IL "I don't care what the unemploy rate is gonna be,its doesn't matter to me.."
— Ryan Williams (@RyanGOP) March 19, 2012
Mitt Romney's campaign pounced on the line, with spokeswoman Andrea Saul emailing reporters: "He Said WHAT?!"
"Wow. Sen. Santorum may not care about the unemployment rate in this country or the nearly 24 million Americans struggling for work, but Mitt Romney does and is running to get people back to work," she said. "If anyone needed evidence that Rick Santorum is an economic lightweight, they needn’t look any further than his various statements today. We're not going to turn around this economy by replacing one former senator with zero job-creating experience with another senator with zero job-creating experience. He has proven it once again."