DES MOINES, Iowa - The Des Moines Register endorsed Mitt Romney tonight, writing that his qualities of "sobriety, wisdom and judgment" make him "stand out as the most qualified Republican candidate competing in the Iowa caucuses."

The Register is the largest newspaper in the state and in a lengthy editorial, it praised Romney as "pointedly refrain(ing) from reckless rhetoric and moralizing" while his opponents have "pandered to extremes with attacks on the courts and sermons on Christian values."

In 2008, the paper endorsed John McCain over Mitt Romney and the editors write Romney "has matured as a candidate."

"Rebuilding the economy is the nation's top priority, and Romney makes the best case among the Republicans that he could do that," the editorial reads.

The editorial has some strong words for Newt Gingrich and Ron Paul, who came in first and second in their Iowa poll just two weeks ago.

"He stands out especially among candidates now in the top tier: Newt Gingrich is an undisciplined partisan who would alienate, not unite, if he reverts to mean-spirited attacks on display as House speaker. Ron Paul's libertarian ideology would lead to economic chaos and isolationism, neither of which this nation can afford," the paper wrote in an editorial that will appear in Sunday's paper.

The paper doesn't mention his other GOP rivals, but writes that Romney "offers smart and well-reasoned alternatives rather than simply proposing to swing a wrecking ball in Washington," a familiar Rick Perry refrain that he often repeats on the campaign trail.

The paper takes on the attack Romney has had a hard time shaking: that he's a "flip-flopper."

"He has evolved from one-time independent to moderate Republican in liberal Massachusetts to proud conservative today. He does not deny changing his position on some issues, but he will say he has made mistakes and has learned from them. Though Romney has tended to adapt some positions to different times and places, he is hardly unique. It should be possible for a politician to say, 'I was wrong, and I have changed my mind,'" the editors write.

They praise the former Massachusetts governor's "tendency to carefully pick his way through the political minefields," using abortion as an example.

"He was quoted in 1994 as defending a woman's right to choose abortion. When he ran for governor in 2002, Romney said he was personally pro-life but vowed he would not restrict or promote access to abortion. Yet he vetoed legislation legalizing the so-called morning-after pill because he saw it as easing access to abortion," the editorial reads. "Voters will have to decide for themselves whether such subtly nuanced statements express Romney's true beliefs or if he's trying to have it both ways."

Although the paper has the largest circulation in the state and this will undoubtedly raise expectations, it is unclear how influential the endorsement will be with Republicans here, since many see the editorial page as having a liberal bent.

Craig Robinson, the former political director of the Iowa Republican Party who now runs TheIowaRepublican.com says it's "an important endorsement for Romney."

"He hasn't campaigned much in the state and it's his second big endorsement. It's something he can easily use in an ad and it shows that some Iowans still like him," Robinson said. "People read it, but it doesn't really influence their votes. Republicans are very skeptical of it."

The Sioux City Journal also endorsed Romney earlier this month.

Robinson said that Republicans in the state expected the paper to endorse Romney, but many see the paper and "especially the opinion page as completely out of touch with most conservatives."

The campaign sent out a press release of the editorial and the candidate tweeted: "@mittromney: Proud to receive the @DMRegister's endorsement! Looking forward to being back in Iowa soon http://t.co/0WOAfC3V #Mitt2012 #IACaucus"

Michele Bachmann is the first of his opponents to react, releasing a statement that says, "I respect the decision of the Des Moines Register editorial board, but I disagree with their rationale and analysis of my campaign." Bachmann is referring to the "snapshots from our interviews" that the paper published after each editorial meeting. They described Bachmann as "virtually sprint(ing) through the newsroom and talk(ing) at an equally rapid clip."

"She unapologetically reeled off a litany of tea party ideals, including abolishing Great Society programs, shrinking government and eliminating the entire federal tax code (though she wants even poor people to pay taxes). Overall impression: An impressive fireball who can absorb and regurgitate tons of information, even if some of it turns out to be inaccurate," the snapshot that was published previously and after each interview read.

Throughout the campaign, Romney has chosen to focus more on New Hampshire, where the first primary votes are cast, as opposed to Iowa, where in just over two weeks caucus-goers will begin the voting process. Yet, New Hampshire's largest paper, the Union Leader endorsed Gingrich last month. Romney has only made six visits to Iowa.

The Register says the editorial board met with all the Republican candidates who campaigned in the state, noting that they extended an invitation to Jon Huntsman, who did not respond to their request. Last week the editorial board met and worked towards a decision.

ABC News' Russell Goldman and Emily Friedman contributed to this report.