Rainier Ehrhardt/AP Photo

Mitt Romney said he is a "concerned" about what may happen in Iraq following the troop withdrawal and said that President Barack Obama will be "vulnerable" when defending his economic policies during the general election in a wide-ranging interview on Fox News Sunday with Chris Wallace.

In his first Sunday morning talk show appearance in nearly two years, Romney told Wallace that while he has a very "high threshold," when it comes to sending U.S. troops into combat, he has reservations about Obama's removal of troops from Iraq.

"I think we're going to find that this president by not putting in place a status in forces agreement with the Iraqi leadership has pulled our troops out in a precipitous way and we should have left 10,000, 20,000, 30,000 personnel there to help transition to the Iraqis' own military capabilities. I'm very concerned in this setting. I hope it works out. But I'm concerned."

The Obama campaign responded to Romney's remarks about Iraq, telling ABC News: "While he did not outline a mission for them in his foreign policy agenda, Governor Romney has made clear that he would leave our troops in Iraq indefinitely."

Tax Cuts

Asked by Wallace about the president's plan to be a "champion of the middle class," who will "portray the Republican nominee as pushing tax cuts for the wealthy," Romney said it would be the president, and not himself, who would appear "vulnerable."

"He's extraordinarily vulnerable, because we'll say 'how did that work Mr. President? Your four years in office, just how would those programs work? Did the poverty decline in this country or did it go up? How about joblessness? You came into office and said let me borrow $787 billion and I'll keep unemployment below 8 percent, which itself was an extraordinarily high number. And it hasn't been below 8 percent since," said Romney.

"His great failing is he does not understand how this economy works and how his policies have made it harder for this economy to put Americans back to work," said Romney.

Asked for the first time about the photograph that shows Romney and his colleagues as young men with money coming out of their pockets, Romney explained that the photo was taken during a celebrations of a big deal that has raised $75 million.

"That was at the closing of our very first fund [at Bain Capitol]. We went out as a group of folks and said, 'I wonder if we can raise money from other people to organize a company,'…and we were successful," Romney said.

The Competition

Romney also spoke at length about current GOP frontrunner Newt Gingrich, whom he said "cut the legs off" the Paul Ryan plan, a sign that he is an "unreliable leader."

Expounding on his previous comments that Gingrich is "zany," Romney elaborated, "And zany, I wouldn't think you'd call mirrors in space to light highways at night particularly practical. Or a lunar colony a practice idea, not at a stage like this."

Often pegged as a candidate who has trouble relating to voters, Wallace asked Romney if he finds it difficult to open up.

"Not in the slightest," responded Romney, shaking his head. "I think people who know me and interact me that I'm an emotional guy I have very deep feelings about the country… as people get to know me better I think they'll come to a different impression."

Romney and His Wife Ann

And that emotional side peeked through when Wallace went on to ask Romney about his relationship with wife Ann, who has been out on the campaign trail frequently lately and has been dubbed the campaign's "secret weapon."

"She's remarkable woman and she's gone through some tough times," said Romney. "She had diagnoses of MS, she's had breast cancer and my feelings and passion haven't for Ann haven't changed in the slightest over the years only to become stronger."

He described the moment that the MS diagnosis was delivered to them as "Probably the toughest time of [his] life."

"We stood up and hugged each other and I said as long as it's not something fatal I'm just fine," recalled Romney, who said he looked into installing an elevator in their home to help her get around and had researched wheelchairs, should Ann become unable to walk. "Look I'm happy in life as long as I have my soul mate with me. And Ann is and she fortunately has been able to recover the great majority of her health."

"When you think about what makes a difference to you in your life, it's people. Life is all about the people you love," said Romney "We can handle disease, death, that's a different matter. Death, I don't know that I can handle death. Disease and hardship, we can handle as long as we have the people we love around us."