Washington (CNN) -- "Excited" after a meeting Thursday with Mitt Romney, tea party favorite Sen. Jim DeMint urged fellow Republicans to be realistic and rally around the party's eventual nominee, making his plea the same day the ex-governor's chief rival suggested voters would be as well off with President Barack Obama as they would Romney.
In addition to fundraising events, Romney was in Washington to hold talks with DeMint as well as legislators from Pennsylvania and Wisconsin, which hold primaries next month. The legislators included House Budget Committee chairman Paul Ryan, according to GOP aides.
"I'm not only comfortable with Romney, I'm excited about the possibility of him possibly being our nominee," said DeMint, a well known conservative, claiming he was impressed by Romney but stopping short of giving him a full endorsement.
Adding that "I just think we just need to look at where we are," DeMint strongly suggested that rival candidates Rick Santorum and Newt Gingrich should drop out to end the nomination fight and focus the party's efforts on defeating Obama in November.
"I just hope at some point they'll realize whether they can win or not," DeMint said of Romney's top opponents. "If they can't, the best thing they can probably do is to help the one who is going to win."
This apparent call for unity contrasted sharply with the message offered Thursday by Santorum, who has been Romney's foremost challenger in large part thanks to support from conservative voters.
The former Pennsylvania senator said in a San Antonio speech that the only way for Republicans to win was "by giving people the choice ... not someone who is just going to be a little different than the person in there."
"If we are going to be a little different, we might as well stay with what we have instead of taking a risk in what may be the Etch A Sketch candidate," Santorum said.
He was referring to earlier comments from a top Romney adviser, Eric Fehrnstrom, who said his campaign will "hit a reset button" to take on Obama in the fall if Romney wins the GOP nomination. He added, "It's almost like an Etch A Sketch. You can kind of shake it up, and we start all over again."
Romney quickly blasted Santorum's remarks, saying in a statement he was "disappointed to hear that Rick Santorum would rather have Barack Obama as president than a Republican."
"Any of the Republicans running would be better than President Obama and his record of failure," he added.
In this swift retort, Romney was able to turn the tables on an opponent who, along with Gingrich, had sought to play up Fehnrstom's Etch A Sketch remarks for a second day.
They said the adviser's remarks bring into question whether Romney will drop his conservative stances, some of which are different from others he'd taken earlier in his career, in favor of more moderate positions ahead of the general election.
On Wednesday, Santorum's campaign posted a photo on Twitter of the candidate using an Etch A Sketch, saying it showed him "studying up on (Romney's) policy positions."
A website unveiled Thursday by the Gingrich campaign features the Fehrnstrom quote above an Etch A Sketch that highlights Romney's policy shifts when viewers hit a prompt labeled "shake." Written on the drawing toy is "Mitt's Etch A Sketch Principles."
"You have this over-and-over process where he's pro-choice and then he's not pro-choice; he's pro-gun control then he's an NRA member who hunts varmints," Gingrich said of Romney at a campaign event Thursday in Houma, Louisiana. "... If you're serious about changing Washington, D.C., you can't use an Etch A Sketch. You can't have a child's toy for a president."
On the Tea Party Nation website, blogger Judson Phillips wrote Thursday that the Etch A Sketch image "is what conservatives have been warning about for months with Romney."
"He is a liberal. He has no core convictions and as soon as he becomes the nominee, he will move far to the left," Phillips continued.
Romney, who scored the prized endorsement of former Florida Gov. Jeb Bush on Wednesday, explained the Etch A Sketch remark by saying, "Organizationally, a general election campaign takes on a different profile."
"The issues I am running on will be exactly the same," he said. "I am running as a conservative Republican. I was a conservative Republican governor. I will be running as a conservative Republican nominee, at that point hopefully, for president. The policies and positions are the same."
The caricature of Romney as a politically motivated flip-flopper extends far beyond the Republican campaign and right-wing blogosphere.
In an interview broadcast Thursday on Public Radio International, Obama said Romney was "pretending" the health care plan he helped institute as governor of Massachusetts differed from the national plan that Democrats in Congress passed two years ago.
Santorum and other conservatives have repeatedly attacked Romney over the Massachusetts health care plan, while Romney says he never called for implementing such a program at the federal level.
In the radio interview, Obama pointed to similarities between the two plans without mentioning the Republican front-runner by name.
"We designed a program that actually previously had support of Republicans, including the person who may end up being the Republican standard bearer and is now pretending like he came up with something different," Obama said.
This week's Illinois result gave Romney at least 41 of the 54 delegates at stake in the contest to face off with Obama, increasing his total to 562, according to CNN's estimate. Santorum is second with 249, Gingrich third with 137 and Texas Rep. Ron Paul last with 69.
A total of 1,144 delegates is needed to clinch the GOP nomination.
Santorum said he expects to do better in coming primaries and caucuses, including Louisiana on Saturday.
The former senator has made a strong showing in traditionally conservative Southern states, winning Alabama and Mississippi a week ago while Romney finished third.
"This is the last chance, in a sense, for the conservative area of the country to plant their flag, and we felt very good about what Alabama and Mississippi did," Santorum said in an interview Thursday with New Orleans radio station WWL. "They restarted this race again."
Another Santorum victory in Louisiana would continue the pattern of the race, while a Romney win would signal growing support from the conservative base that he needs to finish off his rivals.
Gingrich, who appears increasingly unlikely to mount another comeback after two previous campaign surges, said Thursday he is used to fighting from behind.
"Almost everywhere I've campaigned, because of the way of the money, we start behind and then we gain ground," Gingrich told about 100 supporters in Lafayette, Louisiana.
CNN's Kevin Liptak, Kate Bolduan, Paul Courson, Ted Barrett, Shawna Shepherd and Chris Welch contributed to this report.