BANGOR – A planned campaign stop in the city today by retired Gen. Wesley Clark – on presumptive Democratic nominee John Kerry’s short list of potential vice presidential candidates – has renewed debate among campaign watchers in Maine over who will fill the second spot on the Democratic ticket.

There was consensus on at least one point: It depends.

With the national media champing at the bit for a clue about who will be picked, Kerry has been more adept than most at keeping his choice under wraps, analysts say.

It’s said even family members and campaign aides remain clueless about the candidate’s identity, the unveiling of which is expected either today or Wednesday.

“I’m sure when John Kerry is ready to make an announcement, we’ll all find out,” offered one aide.

Clark will hold a press event in Bangor this afternoon at the Korean War Memorial to announce the formation of a Maine veterans group supporting Kerry. Clark will then travel to Portland for another press event focusing on at-risk youth.

While Clark has been pounding the campaign trail for Kerry, it’s unlikely he’ll be sharing the ticket with him, according to Jim Melcher, a political scientist from the University of Maine at Farmington.

“If Kerry doesn’t already have what Clark can offer, he’s in trouble,” said Melcher, suggesting that while Clark’s military background is impressive it would add little to a ticket featuring a decorated Vietnam War veteran.

Essentially, there are two schools of thought in choosing a VP, analysts say.

One: Choose a candidate who “completes” a presidential hopeful by bringing strengths – either geographic or personality traits – to a ticket the running mate lacks.

Two: Choose a proven leader who inspires confidence if required to take over the country in the event the president is unable to complete his term.

Among those who subscribe to the first school of thought, North Carolina Sen. John Edwards is often touted as a favorite for his skillful oration and easy charisma, the latter of which some say is lacking in the comparatively parochial Kerry.

Another favorite under the first scenario is Rep. Richard Gephardt, the Missouri congressman who some believe could help Kerry in the Midwest and among organized labor.

It’s under the second scenario, according to Sandy Maisel, a Colby College political analyst, that Clark has a legitimate shot at the VP slot.

“He’d be very credible,” Maisel said, although ultimately placing his bet on Gephardt.

Whomever Kerry picks, the announcement along with the buzz around the upcoming Democratic National Convention in Boston should give the Democratic ticket a bounce in the polls.

Both campaigns expect such a bounce, with Bush-Cheney chief strategist Matthew Dowd sending a memo Monday to campaign leadership predicting Kerry will hold a lead of “more than 15 points” coming out of the convention.

On Sunday’s “Face the Nation,” Democratic National Committee head Terry McAuliffe predicted a lead of between 8 and 12 points.

While the bump in the polls may be predictable, the identities of vice presidential candidates are often far less so, said Melcher, who put his money on a Kerry-Edwards ticket – with a caveat.

“I’m almost always wrong about these things,” he said. “And anyone who tells you they know is lying.”