Rick Santorum suspended his campaign for the GOP nomination Tuesday for a whole host of reasons. Overtaking Mitt Romney's delegate lead was all but impossible, and the former Senator didn't want to destroy his newfound standing in the Republican Party. But perhaps most importantly, Santorum's camp had a diminished appetite for being pounded on the airwaves.

Romney and his allied Super PAC, Restore Our Future, were on pace to exceed a combined $56 million spent on TV ads, according to a spending tally by SMG-Delta. Pro-Santorum forces, meanwhile, had aired or booked just about $9 million on the airwaves over the course of the primary season.

Santorum had put virtually all his marbles into Wisconsin, and had he remained in the race he was staring down a more than $2 million barrage from Romney and Co. in Pennsylvania -- a state Santorum simply didn't want to lose. Here's a look at the TV beat down Santorum took in three late primary contests:

Wisconsin: This was the only true contest held on April 3. Santorum wasn't on the ballot in Washington, DC and was polling terribly with Maryland Republicans. So he campaigned hard in the Badger State and received a $3.15 million walloping on TV for his trouble. The result: Romney won the state by 7 points.

Illinois: The state's Chamber of Commerce-type Republicans are Romney's natural constituency and should have been easy pickings for the former Massachusetts governor. But that didn't stop Team Romney from putting up a combined $3.57 million in TV ads. Santorum answered back with about $560,000 of his own advertising. It was the second worst TV drubbing he suffered during the primary campaign. The result: Romney by 12 points.

Ohio: This was a trial by fire for Santorum. He'd tailored his appeal to blue-collar conservatives and the Buckeye State is where these voters roam. With that in mind, Romney and Co. brought out the big guns. Restore Our Future alone spent more than $2.5 million and that was supplemented by $1.5 million dropped by Romney's campaign. With more than $4 million in ads raining down in him, Santorum fired back with about $1 million in ad dollars. Despite Romney's barrage, Santorum came within a point of victory in Ohio.

Overall, Santorum was outspent more than 6 to1 by Team Romney. And despite heading into a general election contest against a well-funded incumbent, Romney sounded relieved Tuesday that Santorum was finally out of his way.

"I congratulate him on the campaign he ran," Romney said. "He has proven himself to be an important voice in our party and in the nation." 

Had Santorum's voice been carried with the same volume on television, it's anyone's guess how much longer the GOP contest would have lasted.