On his first big trip to the first big state of the 2012 presidential race, Republican Newt Gingrich was supposed to start overcoming one of his bigger challenges: transforming his perpetually growing, always-evolving recitations on policy into the simple and coherent message of a White House contender.

The former House speaker instead found himself on the defensive about comments he made a day earlier on NBC’s “Meet the Press,” where he criticized a Republican proposal to partly privatize Medicare and defended a central tenet of the Democratic health-care law that passed last year: that people must bear more of the cost of their own medical care.

The comments unleashed a torrent of criticism from conservatives and forced Gingrich to explain his position. His campaign also released a statement and a video clarifying that he wants to repeal the health-care law backed by President Obama.

“I’ve gone around the country for three years giving speeches attacking Obamacare,” Gingrich told a huddle of reporters at the Holiday Inn here Monday, after speaking to the local Kiwanis Club over lunch. “Now, somebody watches 22 seconds of a TV show and says, ‘Oh, what’s happening?’ Nobody said to Reagan, ‘Oh, you must be soft on communism because you said, ‘I like Gorbachev.’ I am opposed to Obamacare. Obamacare should be repealed. In toto. Not partially. All of it. And then we should have a discussion about what replaces it.”

Similarly, Gingrich played defense over his criticism of a proposal by Rep. Paul Ryan (R-Wis.) to dramatically reduce Medicare costs by privatizing the program for future recipients and limiting the government’s contributions. Among other things, Gingrich called Ryan’s plan “radical” and an example of “right-wing social engineering.”

Ryan responded in a radio interview Monday morning: “With allies like that, who needs the left?”

Gingrich was in Iowa on Monday at the outset of a 17-city swing, his first trip to the state after formally declaring his candidacy last week.

At his first stop, he returned again and again to the central theme of last week’s campaign kickoff video: American exceptionalism.

“Are we in the original sense Americans?” Gingrich asked his audience of about 100. “Are we defined by the Declaration of Independence or our Constitution, or are we increasingly in some kind of European relationship, where the state is important and Washington, D.C., is important, and we don’t really have much to say about it?”

Gingrich’s Iowa swing will take him to coffee shops and diners, a new stage for a politician who became comfortable — and famous — as the intellectual idea factory behind the Republican congressional revolution of the 1990s.

Now, Gingrich must convince Iowans that he has what it takes to be president. His challenges include explaining his stormy term as House speaker, which culminated in the shutdown of the federal government and significant electoral losses for his party. He also will have to address his private life, which includes an extramarital affair with Callista Gingrich, now his third wife.

Several of the Iowans who came to hear Gingrich speak Monday said they were willing to listen on the strength of his ideas. “I’ve always been impressed by Speaker Gingrich’s intellectual capability to understand issues and articulate solutions,” said David Tart, 41, a publishing executive from Dubuque. “He seems reasonable and in touch with the vibe of the country.”

But at least one man felt differently — and strongly so. Russell Fuhrman approached Gingrich after his speech and called him a “disgrace” for criticizing the Ryan proposal.