LOS ANGELES — John Kerry is going to have to decide who he wants to be when he grows up politically. His post-primary campaign has been so dramatically unfocused and ineffectual that — even as George Bush has taken more serious blows to his credibility than any sitting president since Richard Nixon in the first years of his second term — Kerry has not been able to open up a lead nationally or in the essential battleground states.

Kerry is making moves to muscle up his Democratic presidential candidacy, with a $25-million let’s-make-some-introductions advertising campaign, an effort to sharpen his message and a sped-up vice presidential search. The next month will be critical. If he can open a five- to eight-point lead nationally and establish leads that mirror those of Al Gore’s 2000 wins in Democratic-leaning battleground states, his campaign will be sufficiently renewed to make the race. If, on the other hand, he continues to hold even nationally and trail behind Gore’s showings in the states that will tip the balance in the Electoral College, there will come a round of questioning — prior to the Democratic National Convention in July — about whether the party is making the right choice.

Kerry will still be the nominee. Modern political parties lack the flexibility to clean up messes, no matter how obvious the need. The was proven in 1996, when the Republican National Convention dutifully nominated Bob Dole, despite the fact that no honest observer thought he had a chance of winning.

Will Kerry be the Dole of 2004? That’s the question that the Massachusetts senator needs to sort out this month.

The decisions Kerry makes now will determine whether his campaign is for real. And the pressure for some kind of signal is only going to increase as the month passes.

In southern California this week to contribute to Robert Greenwald’s upcoming documentary on media issues, I had a chance to talk with political activists, journalists and entertainment-industry insiders. They were all for getting rid of George Bush. But they were also, to a one, convinced that Kerry’s campaign wasn’t doing what was necessary to accomplish that task. They still thought Kerry would carry California — a must-win state for the Democrats — but they were worried that he was slipping even there. And they were convinced that his failure to come on strong was eliminating enthusiasm for his candidacy.

Writer and activist Arianna Huffington, who has written a good new book about the Bush crowd, Fanatics and Fools, was particularly concerned. A none-of-the-above voter in 2000, she’s determined to achieve regime change in the White House this year and she recognizes that Kerry offers the only realistic hope for sending Bush back to Texas. But she is so worried about Kerry’s cautious campaigning that she has penned a letter to the candidate, which she hopes hundreds of thousands of activists will sign. The letter urges the presumptive Democratic nominee to, “Offer voters a bold moral vision of what America can be. A vision that is bigger than the things that divide us. A vision that brings hope and soul back to our politics and appeals to more than voters’ narrow self-interests. A vision that makes America once again a respected force for good in the world.

(You can learn more about Huffington’s recent projects by visiting her www.fanaticsandfools.org website.)

I don’t know whether a letter will get John Kerry’s attention, let alone whether it will get him to recognize that his campaign really is in trouble. But I do know that it is right to target messages toward Kerry, himself.

Again and again, people asked me: Who is advising Kerry? The answer is that the names don’t really matter.

Like any soon-to-be-nominated presidential candidate, Kerry is getting advice from every corner. The noxious Democratic Leadership Council, which every election season commands Democrats to run as Republican-lite centrists, is indeed bending his ear. But Kerry is getting advice from credible and competent sources, as well.

The problem is that the senator seems to be having a hard time separating the wheat from the chaff when it comes to messaging.And, unfortunately, this is a challenge that only he is in a position to resolve.

No one else but the candidate can cure what ails this presidential campaign. That’s because only the candidate can send the a broad and meaningful message that says his campaign really does promise fundamental change. Kerry cannot count on the “Beat Bush” message to carry him to victory in November. Nor should he assume that just promising to be kinder and gentler than Bush will be enough.

John Kerry needs to present himself as the candidate who offers America a clean break from Bushism.

If he does so, he will win.

If he fails to do so, he will be this year’s Bob Dole — without the sense of humor.