Who should be number two?

WITH THE primaries done, we know who's number one.

Now who should be number two?

Democratic presumptive nominee Barack Obama is turning his attention to that question. On Wednesday, he announced a three-member team to help him select a running mate.

Any discussion of the vice presidency must start with Hillary Clinton, who obviously wants the job and whose supporters are pushing for her to be on the ticket.

That idea has considerable currency among Democrats. But Obama needs to treat the vice presidential slot like a strategic asset and not a consolation - or a reconciliation - prize.

So does picking Clinton make sense for him? No, says one of Obama's prominent Bay State supporters.

"It would be a serious mistake for him to put her on because the narrative of the campaign would be all about her and Bill Clinton," declares Phil Johnston, former chairman of the Massachusetts Democratic Party.

The negatives are obvious: Hillary Clinton remains a polarizing figure with many voters; her husband, who has proved a loose campaign cannon, brings baggage and risks all his own.

Certainly sources close to Obama's campaign are skeptical about the idea.

"The only reason I can see him doing it is if he somehow becomes convinced he wouldn't win otherwise," says one.

Obama isn't in such a situation now. He is currently running slightly ahead of John McCain in national polls. Further, though some of Clinton's supporters have threatened to stay home if she isn't selected, those sorts of threats sound more serious in June than they usually turn out to be in November.

One thing Obama's VP-vetting team may soon discover is that though many names are bandied about, once the real scrutiny begins, the list of people who bring credible credentials without difficult political or personal obstacles becomes much smaller.

Then there's the issue of message. Or, put another way, what's the intended point of the pick?

If Obama decides he needs a woman on the ticket, two-term Kansas Governor Kathleen Sebelius would have to be high on his list. Sebelius has executive experience, cross-party appeal, and a demonstrated record as a problem-solver. And, interestingly, her father was once governor of Ohio.

If his aim is to put an important swing state in the Democratic column, the one name that jumps out is Ohio Governor Ted Strickland. Strickland, who has also served six terms in Congress, knows what it takes to carry the Buckeye State, as he showed in rolling up 61 percent of the vote in 2006.

Still, the macro message of the VP pick is probably more important than a single-state strategy.

One important goal would be to bolster Obama's national security credentials. A favorite target of opportunity for Republicans, national security is an area where McCain is already taking aim.

There, two out-of-office figures merit serious consideration. One is former four-term senator Sam Nunn, 69, of Georgia, a man well-liked in Washington and widely respected for his knowledge of defense matters.

Former senator (and governor) Bob Graham, 71, of Florida, meanwhile, merits consideration both on national security and Electoral College grounds. Although his 2004 presidential campaign flopped, Graham, former chairman of the Senate Intelligence Committee, is smart, well-regarded by former colleagues, and popular in the Sunshine State. His vote against the Iraq war resolution puts him in sync with Obama's early opposition to the war. If selecting him would give the Democrats a strong shot at Florida, he deserves a close look.

Two well-known Washington figures would also add heft and experience. Although neither Joe Biden nor Chris Dodd caught fire as a presidential candidate, both senators raised their stature. Obama is said to have a strong relationship with Dodd, who endorsed him after his own candidacy ended. Biden, chairman of the Senate Foreign Relations Committee, would add sterling foreign-policy credentials.

None of those possible VP picks is as well-known or as high-profile as Hillary Clinton. But that's another reason why one of them would prove a better fit.

Scot Lehigh's e-mail address is lehigh@globe.com.