Rick Santorum's assault on rival Mitt Romney continued Saturday in Romney's home state of Michigan, the site of a hotly contested presidential primary that has the potential to transform the GOP race for the White House.

Speaking to a crowd in St. Clair Shores, Santorum ripped into Romney for his role in implementing a state-wide health care plan as governor of Massachusetts that resembles the Affordable Care Act, dubbed by Republicans "Obamacare."

"We have one candidate that opposed government run healthcare, one candidate that opposed the hoax and politicization of science," Santorum said. "We have another candidate that bought it. Not only bought it but did things as governor of Massachusetts. It's laughable for Gov. Romney to suggest that I am not a conservative. It is absolutely laughable for a liberal governor of Massachusetts suggest that I am not the conservative in this race."

Romney and Santorum are both campaigning in Michigan Saturday ahead of Tuesday's primary. Romney, who was born in Michigan and whose father served as the state's governor, later moved to Massachusetts.

The Romney campaign deployed surrogates, including State Rep. Aric Nesbitt, to the event to rebut Santorum's remarks. Romney's team used the tactic in Florida to rattle Newt Gingrich's campaign staff.

Santorum urged voters to think hard on whether or not they could trust Romney to stick to conservative ideals when the race turns to a competition against President Barack Obama.

"Folks, this is an issue of trust," Santorum said.

Responding to Santorum's comments, Romney's campaign lobbed the charge that the candidate was compinsating for a poor debate Wednesday in Arizona.

"Rick Santorum is a Washington insider who is lashing out at Mitt Romney because he had a terrible debate performance," Romney campaign spokesperson Andrea Saul said. "Back in 2008, Sen. Santorum endorsed Mitt Romney for president because of Mitt's 'conservative' record. Now, Rick's changed his tune. This sounds like another case of Rick Santorum abandoning his principles for his own political advantage."

In his remarks, Santorum expounded on his stance that colleges and universities "indoctrinate" students with liberal propaganda, saying Obama's plan to increase the number of college students revealed an elitist attitude toward vocational education.

"The President of the United States said the other day that every child should go to college," Santorum said. "Why? Because you want to indoctrinate them into the liberal stuff they teach them in college? Every child shouldn't have go to college because not every child wants to go to college or needs to go to college. They need to get training to do a good job but they don't need to go and be indoctrinated by liberal professors."

Santorum also pointed to an alliance he sees forming between Romney and fellow candidate Ron Paul, a congressman from Texas. Santorum first floated the notion of a partnership between the two following CNN's Republican debate in Arizona Wednesday.

"The coordination that I felt at the debate the other night was pretty clear," Santorum said. "I felt like messages were being slipped behind my chair and stuff like that. It is pretty remarkable that in twenty debates Ron Paul has never attacked Mitt Romney and that when he's run his commercials in states, first he ran all his ads attacking Rick Perry, then he ran all of his ads attacking Newt Gingrich, then he ran all his ads attacking Rick Santorum. He's running ads here in Michigan. He's not even campaigning in Michigan."