(CNN) – The fiery Republican nominating battle has forged Mitt Romney as the party's "inevitable nominee," a Romney senior adviser said Wednesday. And when the end is in sight, he continued, other candidates should bow out.
The absence of a GOP challenge could allow Romney to "hit a reset button for the fall campaign," Eric Fehrnstrom said on CNN's "Starting Point."
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But it's what he said next that Romney opponents are jumping all over.
"Everything changes. It's like Etch A Sketch," he said. "You can shake it up and we start all over again."
Rival presidential hopeful Rick Santorum seized on the comment at a Wednesday morning campaign event and said it shows Romney is anything but a consistent conservative.
"He will say what he needs to say to win the election before him, and if he has to say something different because it's a different election and a different group of voters, he will say that, too," Santorum, a former senator from Pennsylvania, said in Harvey, La.
"Well, that should be comforting to all of you who are voting in this primary: that whoever you vote for is going to be a completely new candidate," he said. "Remove all trace of any kind of marks and be able to draw a new picture, maybe a picture similar to when he ran for governor of Massachusetts, not as a conservative."
Later, Santorum's campaign posted a photo on Twitter of the candidate holding an Etch A Sketch while "studying up on @MittRomney policy positions."
Newt Gingrich also responded to the comment with a tweet: "Etch a Sketch is a great toy but a losing strategy. We need a nominee w/ bold conservative solutions."
He later appeared on stage at a Louisiana campaign stop with an Etch A Sketch and criticized Romney's team for using the toy as "a model." He then handed the device to a toddler, saying: "She could now be a presidential candidate. She has her very own Etch A Sketch."
And Democratic groups, including the Democratic National Committee and American Bridge 21st Century PAC, have pounced on the opportunity to highlight Romney's change in tune on a few positions over the years.
The DNC video, for example, features some of Romney's most conservative positions–including his plan to cut federal funds for Planned Parenthood and pledge to veto the DREAM Act–but then argues the candidate would try to abandon those stances in the general election.
"Mitt Romney is trying to scrub his extreme record," the text says in an Etch a Sketch graphic. After being shaken, new text appears: "But there are some things you can't shake off."
Following the viral take-off of his comment, Fehrnstrom sought to turn the dials on the controversy with a clarification Wednesday afternoon.
"I was talking about the race. As we move from the primary to the general election, the campaign changes. It's a different race, with different candidates, and a focus on different issues," he said.
Fehrnstrom, the Romney adviser, made his comments when asked if the continuing challenge from Santorum and former House Speaker Newt Gingrich was driving Romney "so far to the right it would hurt him with moderate voters in the general election."
With Romney's win Tuesday in Illinois, the delegate math is increasingly in his favor. He has 562 delegates and is just shy of half the delegates needed to clinch the GOP nomination. Former Sen. Rick Santorum of Pennsylvania stands at 249, former House speaker Newt Gingrich is at 137, and Texas Rep. Ron Paul has 69 delegates – all less than a quarter of the way towards 1,144, the magic number.
The race for delegates has produced, as in prior contests, sharp language between the candidates.
"Emotions run high. Elbows get sharp and get thrown in different directions," he told CNN's "Soledad O'Brien." "Usually when the contest comes to its natural end in a primary, people get behind the inevitable nominee, and in this case it's Mitt Romney."
Fehrnstrom acknowledged that the decision to enter or exit the race "is a very personal one that can only be made by the candidate."
"But I can speak to what happened four years ago when Mitt Romney stepped aside for John McCain," who went on to win the GOP nomination in 2008, Fehrnstrom said. "At the time, John McCain did not have the delegates he needed to clinch the nomination but he was clearly on a path to doing that. The math was very challenging for Mitt Romney."
Fehrnstrom's comments come as a conservative group behind the tea party movement, FreedomWorks, said in a Washington Times newspaper report that it would no longer protest Romney.
Romney's exit helped McCain, who endorsed Romney this cycle, consolidate the party in his favor. Fehrnstrom suggested a similar case could play out this year.
"Now, in Rick Santorum and Newt Gingrich, these are both decent, honorable men who have run good campaigns," he said, calling them "good Americans" and "good Republicans."
"And ultimately, I'm confident they'll make a decision that's not only right for their party, but right for them."
– CNN's Jim Acosta and Chris Welch contributed to this report.