The most impressive thing about Mitt Romney is his clarity of mind. When he set out to pursue is party's nomination, he studied the contours of the Republican coalition and molded himself to its forms.

Earnestly and methodically, he has appealed to each of the major constituency groups. For national security conservatives, he vowed to double the size of the prison at Guantanamo Bay. For social conservatives, he embraced a culture war against the faithless. For immigration skeptics, he swung so far right he earned the endorsement of Tom Tancredo.

He has spent roughly $80 million, including an estimated $17 million of his own money, hiring consultants, blanketing the airwaves and building an organization that is unmatched on the Republican side.

And he has turned himself into the party's fusion candidate. Some of his rivals are stronger among social conservatives. Others are stronger among security conservatives, but no candidate has a foot in all camps the way Romney does. No candidate offends so few, or is the acceptable choice of so many.

And that is why Romney is at the fulcrum of the Republican race. He's looking strong in Iowa and is the only candidate who can afford to lose an important state and still win the nomination.

And yet as any true conservative can tell you, the sort of rational planning Mitt Romney embodies never works. The world is too complicated and human reason too limited. The PowerPoint mentality always fails to anticipate something. It always yields unintended consequences.

And what Romney failed to anticipate is this: In turning himself into an old-fashioned, orthodox Republican, he has made himself unelectable in the fall. When you look inside his numbers, you see tremendous weaknesses.

For example, Romney is astoundingly unpopular among young voters. Last month, the Harris Poll asked Republicans under 30 whom they supported. Romney came in fifth, behind Rudy Giuliani, Mike Huckabee, John McCain and Ron Paul. Romney had 7 percent support, a virtual tie with Tancredo. He does only a bit better among those aged 30 to 42.

Romney is also quite unpopular among middle- and lower-middle class voters. In poll after poll, he leads among Republicans making more than $75,000 a year. He does poorly among those who make less.

If Romney is the general election candidate, he will face hostility from independent voters, who value authenticity. He will face hostility from Hispanic voters, who detest his new immigration positions. He will face great hostility in the media. Even conservative editorialists at places like the Union Leader in New Hampshire and The Boston Herald find his flip-flopping offensive.

But his biggest problem is a failure of imagination. Market research is a snapshot of the past. With his data-set mentality, Romney has chosen to model himself on a version of Republicanism that is receding into memory. As Walter Mondale was the last gasp of the fading New Deal coalition, Romney has turned himself into the last gasp of the Reagan coalition.

That coalition had its day, but it is shrinking now. The Republican Party is more unpopular than at any point in the past 40 years. Democrats have a 50 to 36 party identification advantage, the widest in a generation. The general public prefers Democratic approaches on health care, corruption, the economy and Iraq by double-digit margins. Republicans' losses have come across the board, but the GOP has been hemorrhaging support among independent voters. Surveys from the Pew Research Center and The Washington Post, Kaiser Foundation and Harvard University show that independents are moving away from the GOP on social issues, globalization and the roles of religion and government.

If any Republican candidate is going to win this year, he will have to offer a new brand of Republicanism. But Romney has tied himself to the old brand. He is unresponsive to the middle-class anxiety that Huckabee is tapping into. He has forsaken the trans-partisan candor that McCain represents. Romney, the cautious consultant, is pivoting to stress his corporate competence, and is rebranding himself as an Obama-esque change agent, but he will never make the sort of daring break that independent voters will demand if they are going to give the GOP another look.

The leaders of the Republican coalition know Romney will lose. But some would rather remain in control of a party that loses than lose control of a party that wins. Others haven't yet suffered the agony of defeat, and so are not yet emotionally ready for the trauma of transformation. Others still simply don't know which way to turn.

And so the burden of change will be thrust on primary voters over the next few weeks. Romney is a decent man with some good fiscal and economic policies. But in this race, he has run like a manager, not an entrepreneur. His triumph this month would mean a Democratic victory in November.

c.2008 New York Times News Service