Talk to any Republican leaders or strategists and they will quickly point to the enthusiasm gap between their voters and President Obama’s as one reason they believe they will prevail next November. Listen to any Republican voters and a different enthusiasm gap appears. They are not truly excited about any of their likeliest nominees, least of all Mitt Romney.

The former Massachusetts governor is rapidly becoming a one-man political experiment, testing the theory that empathy and the ability to connect with voters are prerequisites for a winning campaign. He has many attributes, but firing up a Republican crowd isn’t one of them.

The lone Republican candidate who once seemed to charge up Republican audiences was Herman Cain. But the businessman-politician was on a downward slide even before Saturday’s announcement that he would suspend his campaign. By the time of his announcement, Cain was a rear-view mirror candidate; Republican voters had moved on.

Romney’s predicament has been in neon lights this past week. A Time Magazine cover story by Joe Klein blares, “Why Don’t They Like Me?” A New York Times Magazine story by Robert Draper asserts that the Romney campaign has “taken a smart and highly qualified but largely colorless candidate and made him exquisitely one-dimensional: All-Business Man, the world’s most boring superhero.”

When Romney showed some emotion last week, it was not the kind that political experts would recommend. In an interview with Fox News anchor Bret Baier, he squirmed in his seat with discomfort and let his exasperation show over some tough but totally within-bounds questions about changes in his positions over the years. Baier later said that, after the interview, Romney upbraided him for being “overly aggressive.” So much for being a happy warrior.

On Thursday night, 12 Republican voters sat down with pollster Peter Hart for a focus group, one of a series being conducted for the Annenberg Public Policy Center at the University of Pennsylvania during the election. When Romney advisers watch the video on C-SPAN, they should wince, though they no doubt have seen and heard the same thing in their own research for months.

Some of the participants offered positive appraisals of Romney as a man of good values and high morality. He was seen by a majority as fully experienced to be president — as was former House speaker Newt Gingrich. But the consistent theme that came through was that Romney was not one of them — not one of the 99 percent. Asked in a variety of ways to assess and analyze Romney’s character, the participants described him in terms that made him seem aloof, inauthentic and privileged.

Hart asked them, if Romney were a member of your family, who would he be? One said a second cousin, which is to say someone not considered close. Another said distant “because he’s richer than the rest of us.” Another said the “dad who’s never at home.” Another said Romney wouldn’t have time for his extended family.

Hart asked them to imagine each of the candidates standing sixth in line at the airport. There is one ticket available for the upcoming flight and the candidate needs to be on the plane. How would each of them manage to try to get to his destination? Of Romney, nearly everyone offered a variation of the same theme: He would buy his way onto the plane by paying off someone to get the ticket.

When they were asked which of the candidates they would ask to be their single character witness if they were unjustly accused of a crime, many more picked Michele Bachmann or Ron Paul than named Romney.

When they were asked which of the candidates they would most like to spend a weekend with, only two said Romney — one because he thought he would get a taste of Romney’s affluent lifestyle, the other because he opposes Romney right now and said he would want to ask him a lot of questions to decide whether he was right or wrong in his assessment.

“So it’s a pain weekend?” Hart said.

Romney’s advisers long ago digested the absence of love for Romney among Republican voters and constructed a campaign designed to win in spite of that problem rather than trying to do something about it.

Their theory is that voters are not looking for inspiration or empathy so much as they want someone with the experience to turn around the economy. They may believe, with some justification, that in a choice between Romney and Gingrich, Republican voters will see Romney as the safer and better bet.

They may turn to surrogates like New Jersey Gov. Chris Christie to provide the charisma and excitement lacking in their candidate. Ultimately, they will sell Romney as the most electable candidate to the rank and file, who find little else to inspire them about him. But Romney’s challenge will be to make that sale more effectively than he’s done so far.

Republican leaders are counting on anti-Obama sentiment to keep the enthusiasm gap tilted in their favor next year, regardless of the limitations of their own nominee. Perhaps they are correct. But if they end up with a candidate that even many of their own voters see as not someone who walks among them and for whom they feel so little passion, that intensity gap may be perilously small.