Washington (CNN) -- Newt Gingrich said Sunday that he'll do everything he can to support Mitt Romney as the Republican Party's presidential nominee when that time comes. But that time hasn't come yet.
"I think you have to be realistic, given the size of his organization, given the number of primaries he's won. He is far and away the most likely Republican nominee," Gingrich said on "Fox News Sunday." "And if he does get to 1,144 delegates, I'll support him. I'll do everything I can this fall to help him defeat (President Barack) Obama."
But while he appears to accept Romney's inevitable nomination, Gingrich won't give up on trying to influence the party's platform that emerges going into the general election.
"I think platforms matter in the long run in the evolution of the party. And the party is more than just a presidential candidate -- it's Senate candidates, House candidates, state legislators," he said.
Gingrich capitalized on conservatives' misgivings about Romney early in the campaign. Strong debate performances while conservative rivals Rick Perry, Herman Cain and Michele Bachmann faltered propelled him to the top of polls late last year.
But Romney's machine interrupted his "glide path" to the nomination with a barrage of attack ads.
"I'd say the glide path started to have to run into anti-aircraft called 'Romney,' " Gingrich said Sunday.
Despite the vicious personal attacks, Gingrich said he accepts that as part of the game.
"I hit him as hard as I could. He hit me hard as he could. It turned out he had more things to hit with than I did. And that's part of the business," he said.
Gingrich said he thinks Rick Santorum, Romney's nearest pursuer, is seeing that now in Santorum's home state of Pennsylvania, which votes with four other states on April 24.
While Romney tries to focus on the general election campaign against Obama, a super PAC supporting him will reportedly launch a $2 million ad blitz in Pennsylvania in an effort to land a knockout blow on Santorum.
"it's clear that Governor Romney has done a very good of building a very substantial machine. And I think Santorum is discovering in Pennsylvania right now -- it's a challenge," Gingrich said.
Santorum canceled campaign events for Monday after daughter Isabella, who suffers from a chromosomal condition called Trisomy 18, was hospitalized for the second time this year.
He had not announced public events for the coming week but his campaign had previously said he would resume campaigning Monday after taking the Easter weekend off.
After speculation arose that Santorum might be preparing to drop out, his campaign on Saturday released a schedule of events for Tuesday through Friday.
Asked Sunday if Santorum should get out of the race, Gingrich said, "No, I think he has to make that decision."
The long campaign and the punches and counterpunches from Romney and Santorum have taken their toll on the presumed nominee, especially among independent voters, according to a recent USAToday/Gallup poll of independents in swing states.
"I think Romney through the primaries has been beaten up by the others, seen as removed from, kind of, the middle-class, average voter. Has trouble with women now, with Latinos," said Democratic strategist and pollster Mark Penn on CNN's "State of the Union" on Sunday. "Boy, I think he's entering the general election now kind of -- a totally beaten-up candidate and this poll is a reflection of that."
But Republican pollster and strategist Linda Divall said that's normal in a campaign and there's time to repair the damage.
"Number one, it's early April. Number two, when you look at it with registered voters, the margin becomes much closer. Thirdly, this is not atypical in a very competitive Republican primary, that our nominee tends to go down," she told "State of the Union" anchor Candy Crowley.
"The other thing that's stymieing Mitt Romney somewhat is the perception of the Republican Party, which has also suffered a little bit of a beating," she said. "So, I think as the Romney campaign is able to regroup, bring in their general election team, and strike some very clear themes between himself and the president, which they started to do with the speeches the last few days... you'll see a pretty stark contrast in terms of what is the direction that this country should be pursuing -- in terms of the economy and jobs and getting the deficit under control."
Gingrich said Sunday that he thinks Romney will adopt some of the positions that he's advocated -- energy independence, personal Social Security accounts -- the "Chilean model" that he has pushed -- keeping the government from trying to impose itself on religious values and paying down the debt. He said revenue from expanding domestic energy should be directed toward that.
And Gingrich said he has already talked to Republican National Committee Chairman Reince Priebus about working in the fall "to help defeat Obama any way I could -- whatever the team thinks I can do to be helpful, I would do."
Beyond that, he said he wouldn't want to serve in a Romney administration and would rather "go back to a post-political career."
He said he'll have no regrets about his campaign.
"I'm glad I did this," he said Sunday. "For me, it was important as a citizen to try to do some very hard things, to try to bring ideas and new approaches.
"It turned out to be much harder than I thought it would, but it was the right thing for me to do at that point, both in my life and for where I though the country was."
CNN's Kevin Bohn and Kevin Liptak contributed to this report.