The hug shared by John Kerry and Bob Shrum aboard the Massachusetts Senator’s campaign bus last January was more than 30 years in the making.

The two men had spent decades preparing for such a moment; early exit polls had predicted Kerry would be the winner of the Iowa caucuses, a seeming impossibility just a few months before.

Forgotten in that outpouring of emotion was that the moment could easily have never happened. Kerry and Shrum’s relationship had been severely strained just a year earlier when the media consultant was faced with a choice between the Bay State Democrat and another client — North Carolina Sen. John Edwards (D).

Shrum agreed to work with Kerry, helped him to the nomination and then watched as he fell to defeat last November at the hands of President Bush.

With consultants now seen as an essential part of the fabric of any winning campaign, the race for top talent has become increasingly heated among the handful of politicians eyeing the White House.

For the candidate able to land the hot consultant of the cycle, a boost in credibility among the party kingmakers is almost certain to follow. Losing out on a coveted firm can take the shine off a budding candidacy, making it more difficult to recruit other top-tier staff and raise the millions needed to run a national campaign.

No fewer than five consulting firms have multiple candidates mulling over 2008 presidential runs.

Two polling companies — Public Opinion Strategies on the Republican side and Garin Hart Yang for Democrats — have five and four would-be clients, respectively, placing them at the center of the talent primary.

“No decisions have been made about how we are working with presidential candidates if they do run,” said Glen Bolger, a founder of Public Opinion Strategies. “It will be an interesting partner meeting figuring that one out.”

Anita Dunn, a Democratic media consultant with Squier Knapp Dunn, said that in many instances, consultants are rooting against their own financial interest in order to avoid conflicts.

“At this stage most firms hunker down and hope most of their clients will decide not to run,” said Dunn, who currently has only one client expected to run for president in 2008: Indiana Sen. Evan Bayh.

But in 2000, Dunn faced a consulting conflict when former New Jersey Sen. Bill Bradley decided to take on Vice President Al Gore in the Democratic presidential primaries.

Dunn, who had long ties to Bradley, took a leave of absence from the firm to work for her former boss. Meanwhile, Squier Knapp Dunn remained as Gore’s media consultant.

The talent primary is perhaps the most behind-the-scenes of fights in the run-up to the nomination — but also one of its most important.

“The truth of the matter is that because we don’t know the result of the horse race before it is run, we try to virtually run it in surrogate and metaphorical ways,” said Shrum, now a senior fellow at the New York University Wagner School of Public Service.

“Who has the most money? Whoever gets consultant ‘X’ has a leg up,” Shrum added. “What matters in the end is the work [the consultants] do.”

But, perception does matter, and winning a fight for a sought-after consultant or firm lends momentum to a candidacy in the inner circles of political Washington.

Even though few firms dealing with cross-pressures from the 2008 presidential contest publicly acknowledge the decision they face, several consultants have already made choices.

Mark Penn, a partner in the Democratic polling firm Penn, Schoen and Berland, parted ways earlier this year with Bayh to devote full attention to New York Sen. Hillary Rodham Clinton.

Penn’s relationship with Bayh went back to the Indiana Senator’s first run for governor in 1988; the pollster had been affiliated with the Clinton family only since 1996 — when he helped re-elect President Bill Clinton to a second term. Penn also handled the survey research on Clinton’s 2000 Senate bid. Penn did not return calls seeking comment on his decision.

More recently, Mark McKinnon, who rose to fame by directing the advertising for the 2000 and 2004 campaigns of President Bush, acknowledged that he is in discussions with Sen. John McCain (R-Ariz.) about serving as his media consultant in 2008.

McCain also has ties to several other Republican firms.

In his 2000 insurgent bid, McCain’s media campaign was handled by Mike Murphy, a consultant now affiliated with a firm known as the Navigators, which is based in California.

Murphy was also a lead strategist for the 2002 victory of Massachusetts Gov. Mitt Romney (R) — another potential 2008 candidate.

Given his divided allegiance, Murphy has pledged not to work for either McCain or Romney if both men decide to make the 2008 race.

Murphy also counts Florida Gov. Jeb Bush — who has brushed aside speculation that he will be a 2008 candidate — as a client.

McCain’s 2008 team will likely be McKinnon and Public Opinion Strategies’ pollster Bill McInturff, who has worked with the Arizona Senator since he was first elected to the body in 1986. McCain is also certain to rely on the counsel of John Weaver and Rick Davis — two of the masterminds behind his 2000 campaign.

Should Murphy keep to his pledge to remain above the fray in 2008, Romney could turn to Greg Stevens, a partner in Stevens, Reed, Curcio and Potholm — one of the largest and most influential Republican media firms.

Stevens handled Romney’s unsuccessful 1994 Senate race against Sen. Edward Kennedy (D-Mass.), but the candidate is not currently a Stevens Reed Curcio and Potholm client.

Stevens’ firm, however, has also worked with McCain (a current client) and Virginia Sen. George Allen (R) since the latter’s 1993 gubernatorial campaign — though Stevens’ services have not been retained for either Allen’s 2006 re-election effort or a potential 2008 race.

One of Allen’s main rivals for the GOP nomination, Tennessee Sen. Bill Frist, also has ties to Stevens’ firm; Paul Curcio, one of the name partners, has handled Frist’s media campaigns in past races. Curcio has not signed on for a presidential bid.

Reached Tuesday, Stevens said only that it is “very early” to begin thinking about potential client conflicts.

Rick Reed, another partner in the firm, said “we are not cross-pressured until we know who’s running.”

Confused yet?

The consultant situation on the Democratic side is only slightly clearer.

Garin Hart Yang leads the Democratic pack with four potential candidates, although two (Wisconsin Sen. Russ Feingold and Tennessee Gov. Phil Bredesen) are either not considered particularly serious or are long shots to run.

Virginia Gov. Mark Warner and retired Gen. Wesley Clark are also Garin Hart Yang clients and, by all indications, are planning to make the 2008 race.

John Edwards also finds himself at a consultant crossroads as he approaches a possible 2008 bid.

In 2004, Edwards used Harrison Hickman, now of Global Strategy Group, as his pollster, a connection likely to continue.

On the media side, however, Edwards is likely to face a choice.

For almost his entire 2004 primary campaign, Edwards used David Axelrod of AKP Message and Media, but at the end of that race he turned to Marius Penczner as his lead media consultant.

The Edwards team still lists both Axelrod and Penczner as media consultants when asked. For its part, AKP is not currently working with Edwards though Axelrod and the former North Carolina Senator remain close, according to informed sources.

Although Penczner was an independent operator in the last election, he has since joined forces with Penn, Schoen, Berland and Associates.

A look back at recent presidential primary history could provide some clues to how consultants will handle their upcoming choice.

In 1988, the late Bob Squier of Squier Knapp Dunn had worked for almost every candidate mentioned as a possible presidential nominee.

Squier’s client list included Delaware Sen. Joseph Biden, Tennessee Sen. Al Gore, Illinois Sen. Paul Simon, Colorado Sen. Gary Hart and the eventual nominee, Massachusetts Gov. Michael Dukakis.

Rather than picking and choosing, Squier decreed that the firm would not be involved in any of the primary campaigns.

“That was the easiest way for him to handle it,” said Dunn. “It did cost him some Senate clients.”

CORRECTION:Following the 2004 election, Marius Penczner joined Penn, Schoen, Berland and Associates, not Shrum DeVine Donilon as was originally reported (“Consulting Firms Facing Conflicts in 2008,” June 20).

Also, Mike Murphy, a media consultant, was a lead strategist during Arizona Sen. John McCain’s (R) 2000 presidential bid. He was not, however, the lead ad man as implied. That title belonged to Greg Stevens.