The moment of truth is about to arrive for Mitt Romney. Though one of his advisers was quoted recently as saying, “I don’t see any scenario where we’re not the nominee,” the former Massachusetts governor needs to finish in the top tier in Iowa on Tuesday and notch a decisive victory the following week in his neighboring state of New Hampshire. If he can’t pull that off, he could still lose the Republican nomination.

Romney has been a front-runner for much of the past year, but support for his candidacy has hovered around 20 percent. And that ceiling is an obstacle for a presidential candidate who describes himself as the most electable and whose strongest arguments revolve around his potential performance in a general election and his real-world experience.

Changes in the Republican nominating process this cycle, particularly allocating delegates proportionally in the early primaries and caucuses, mean that it will be nearly impossible for Romney or any other Republican to achieve an early victory, as Sen. John McCain and George W. Bush did in the most recent GOP nominating contests.

I have worked on presidential campaigns for five Democratic nominees and produced hundreds of television ads for political candidates across the country and around the world. While many think that TV ads are a dying form of communication, I believe they could be the decisive factor in this campaign. That’s why the Republican candidates and their super PACS spent more than $10 million in Iowa in December, and why a barrage of negative ads against former House speaker Newt Gingrich took him from first in Iowa to a distant third place in some polls.

If Romney runs the right ads — which he has the resources to do — he can seal the nomination, even if a surge by Ron Paul or Rick Santorum spoils his day in Iowa.

I saw firsthand the impact of powerful primary advertising with a number of the candidates I worked for, including Mike Dukakis, Al Gore and John Kerry. The biographical ad we produced for Gore in the fall of 1999, when he trailed Sen. Bill Bradley by 10 points in New Hampshire, positioned the vice president to win in the Granite State in 2000; the emotional ad for Kerry in Iowa featuring one of his swift boat crewmates had an enormous impact on voters there. And the devastating negative attack that we launched for Dukakis against Rep. Dick Gephardt, calling him a “flip-flopper” after he won Iowa, helped lead Dukakis to victories in a number of states on Super Tuesday.

As an admaker speaking from the safe sidelines of the other party, I believe that Romney is only three ads away from winning the Republican nomination.

‘Ann’s Story’

The first ad Romney should produce is a testimonial featuring his wife talking about her husband’s character and the fact that he has supported her through her fight with multiple sclerosis. This spot would be the most effective kind of positive ad, one that promotes a candidate while cutting deeply against an opponent’s most conspicuous weaknesses — in this case, Gingrich’s adultery. It would also showcase Romney as a steady person of integrity, a contrast with the outrageous statements published in a newsletter that bore Paul’s name. Ann Romney can make a simple but powerful argument that her husband stood by her through tough times — her illness — and that he is prepared to stand by America in tough times as well.

The ad would allow Mitt Romney to deal with the perception that he is out of touch and that his wealth has insulated him from adversity. Though his wife has discussed her illness on the stump and in interviews, the presentation of this information in a TV ad would be powerful and would cut through the political clutter of the ads that now dominate the airwaves. We are past the point of subtlety in this process. It is time for Team Romney to put the strongest testimony — Ann Romney’s — to the jury.

‘Georgia Voices’

The second ad Romney should run is a negative spot against Gingrich. While Paul or Santorum may be the surprise winner — or “surpasser of expectations” — in Iowa, Romney needs to get rid of the former House speaker, who still has a strong shot in South Carolina.

This attack ad would not feature a narrator, as is typical of many of the negative ads so far. Instead, it would be a “man on the street” spot. An ad like this almost derailed the first candidate I worked for, Jimmy Carter, when he ran against Gerald Ford. The Ford campaign went to Georgia and asked people about Carter as governor, and many of those Georgians had some nasty things to say.

Sending a camera crew to Gingrich’s old congressional district in Georgia would, I believe, yield a similar result. A lot of people don’t like Gingrich, and to go back to his home base and let people speak about his flaws — from his marital infidelities to his cozying up with Democrats on issues such as climate change — could be devastating. Those real voters whom Gingrich once represented could have an enormous impact in South Carolina and Florida — Georgians look and sound a lot like their neighbors. And voters give these types of ads, assuming they are not staged, more latitude in terms of how tough they can be, compared with the more traditional negative ads in which a narrator lists a candidate’s flaws.

I know this well — and so should Romney. I produced a series of testimonial ads against him for Sen. Ted Kennedy’s reelection campaign in 1994. They featured workers from a Marion, Ind., plant that Romney’s firm, Bain Capital, had taken over and devastated. And if Paul or someone else becomes the Republican flavor of the week, an ad like this (“Texas Voices,” for instance) from that candidate’s home base would be equally damaging.

‘A Future to Believe In’

The third ad the Romney campaign should run would feature the “candidate to camera” — still the single most powerful technique in political advertising. Barack Obama used such ads consistently in his campaign four years ago. Romney needs to connect with voters, to tell them why he is running for president and what he will do to change the country’s direction. He needs to talk about creating jobs and focus relentlessly on the future. Romney has the look and presence to pull off a presidential spot. Since he has some of the best admakers in the Republican Party working for him, there is little doubt that they could make it work.

Voters put a premium on live and unfiltered events. Romney speaking to the camera in an honest and compelling way is the closest his campaign can come to recapturing that dynamic. While the Romney camp has attempted to do this in several ads thus far, using footage from the debates and from speeches, those settings only underline the political dimension that Romney should try to avoid. He may be asking voters to “Believe in America,” but his real challenge is getting them to believe in him. Speaking directly to them is the best way to overcome that obstacle.

To win the nomination, Romney should be prepared to do what Kerry did in 2004: Make sure his campaign has the resources it needs to win the early states and gather the momentum necessary to secure his party’s nod. Kerry chose in the primary process to go outside the public funding scheme for a simple reason — Gov. Howard Dean was likely to do so, giving him an inordinate advantage.

Romney must likewise be prepared to put his own wealth into the race, as Kerry did. Romney did so in the last campaign and has been reluctant to do it this time. But he needs a dominant paid media presence in South Carolina and Florida — not just a couple of weeks of TV ads, but a sustained television fight.

Past advertising campaigns — from Carter to Dukakis, from Kennedy to Kerry — provide a road map that could propel Romney to the Republican presidential nomination. If he pulls it off, he could be a formidable opponent for President Obama. If he doesn’t, it means he has lost not to a strong and proven foe such as McCain, but to the weakest Republican field in my lifetime.

Tad Devine is a Democratic media consultant who worked for five of his party’s presidential nominees, including as a senior adviser to Al Gore and John Kerry.