It could not have been Hillary.

Despite her hefty take of the primary votes -- 18 million is the commonly reported number -- there was simply too much bad water under the bridge.

Not everything negative counts as bad water. Much of it can be chalked up to the vagaries of high stakes campaigning. It is, in short, the way the game is played.

But in some instances, the Hillary camp crossed the narrow strait between competitiveness and contempt.

It started in South Carolina, where, intentionally or not, Bill Clinton came dangerously close to painting Barack Obama as a light-weight token and the state’s black voters as sheep who are naturally drawn to the black shepherd. Black South Carolinians turned out big for Jesse Jackson back in 1988, he noted.

If Clinton had derisive intentions and thought he was covered by code, he learned quickly how bilingual many people are. If his trip into the danger zone was sheer mishap, it suggested that he’s lost his touch as the supreme political maestro of our times.

Either way, it was a hard blow to the solar plexus -- the core that has kept the Clintons’ popularity toned, upright and strong in America’s black community since they first exploded onto the national scene in 1992.

Later, Hillary socked it to Obama on the readiness issue -- tough and maybe unfair, but allowable under the terms of engagement -- but coupled it with a tribute to John McCain, the man poised to be the Democrats’ foe in November, no matter whom the donkeys chose.

Then there was the refusal to acknowledge the handwriting on the wall, a stance her supporters couched as “tough” or “determined,” but which many Obamaphiles saw as intransigence built on a sense of entitlement.

So it was that, when the phone call was placed, it went to Joseph Biden, the scrappy foreign policy maven and veteran U.S. senator from Delaware. Biden had thrown a few punches at Obama during the primary season too, but his were within bounds. And when he left the race, he cut bait. He didn’t keep his supporters on edge, riled up and rattling off demands as if the nomination were a pie to be shared. There was one slice, and Obama got it.

Biden is the experienced, nuts-and-bolts practitioner that Obama -- a big picture man -- needed. Hillary’s experience could not compare.

Biden’s street fighting also complements Obama’s street cool. Where Obama fails at political fisticuffs because he is too urbane and conciliatory by nature, Biden has no reservations about biting back. However much of a fighter Hillary may be, having her as Obama’s attack dog would not have gone down the same. She would have been portrayed as a rhymes-with-witch every time she opened her mouth in retort.

Little wonder, then, that the Republicans are having a conniption. They had been pining for Hillary Clinton on the ticket so they could paint her all up as a shrew and get the misogynists and stuck-up women all hot and bothered.

Now that she didn’t make the cut, the GOP, shameless to its bone marrow, is blasting Obama as a traitor -- moreover, as a man with a grudge who passed Hillary over “for telling the truth.”

Hillary’s campaign rebuked that and swiftly, but the response seemed to be low on the outrage meter.

Either her heart still isn’t behind Obama or she’s run out of fight.