The presidential candidacy of New York Mayor Michael Bloomberg is already a smashing success.

A mere change of registration from Republican to independent has garnered him a cornucopia of free and favorable publicity some candidates do not receive in a year of campaigning.

The mayor has replaced Fred Thompson as the most talked-about non-candidate since Mario Cuomo in 1992 and Colin Powell in 1996. Gov. Cuomo and Gen. Powell, after scouting the terrain, declined to engage. That may be good advice for the mayor. Enjoy and exploit the media frenzy you will create between now and decision day, but think long and hard before plunging in. For, after that, the fun stops, the risks of national humiliation rise, and you are fair game for hostile media and the opposition researchers.

While impossible to see how Mayor Bloomberg can win, even if he spent $2 billion, it is easy to see how he sinks Hillary Rodham Clinton. For the more popular he makes himself with his media buys, the more votes his candidacy attracts, the more certain it is that he does for the Democratic Party what Ross Perot did for the GOP in '92.

How so? First, the mayor is Jewish and is best-known and most loved among Jewish voters and denizens of the Big Apple, where he is more popular than Rudy. Both constituencies are Democratic.

Even in his 49-state triumph, Richard Nixon won only a third of the Jewish vote. In his 49-state landslide, Reagan carried even less. In 2006, by one survey, the Jewish vote went 88 percent Democratic. As for New York City, that has long been the Democrats' key to New York State.

The first effect of a Bloomberg candidacy would be to siphon off perhaps 2 million votes from Hillary in New York, putting the state in play for the Republicans. The same would be true in New Jersey and Connecticut.

Second, though the mayor is being painted as a "post-partisan" problem-solver, he is a textbook nanny-state liberal, who has outlawed smoking in neighborhood bars, wages war on trans-fats, and is anti-gun, pro-gay rights and pro-abortion.

Had Bloomberg run in the Republicans primaries, his billions would not have bought him the nomination, which is why he left the party. Indeed, if he could buy the GOP nomination, the party would leave him.

At heart, Mike Bloomberg never really belonged to the GOP. It was a marriage of convenience he dumped at the first opportunity. And no blitz of media ads is going to convince this country he is other than what he is: a cookie-cutter New York social liberal.

Another reason it is unlikely a Bloomberg candidacy will carry a single state is that he is neither charismatic like John F. Kennedy nor a conviction candidate like Barry Goldwater, and he is certainly not the combination of the two that Ronald Reagan was. Continued...