In recent weeks, both Hillary Clinton and Barack Obama have taken time off the campaign trail to sneak down to Chapel Hill, North Carolina, to personally seek one of the most important endorsements left this campaign season. While several top Democrats remain uncommitted, few nods would generate headlines like John Edwards' blessing.

Reports have suggested Edwards is considering backing both candidates. While on the stump, he seemed closer to Obama's change message. But Edwards is also said to be considering Obama's lack of response to attacks as a potential weakness, leaving the door open for the one-time candidate to back Clinton, an outcome that would certainly carry considerable weight.

Edwards attracted support from lower-income white males, a group whose support would boost either Clinton or Obama to a majority. Whether those voters would follow Edwards is a separate question, but his endorsement would go a long way toward convincing many to coalesce behind one of the remaining candidates.

But Edwards' endorsement would require a careful choreography. While in the race, Edwards unabashedly acted as the attack dog, hitting Clinton as an agent of the status quo and, toward the end, criticizing Obama's perceived lack of willingness to fight. Edwards is much better at attacking opponents than Clinton or Obama: When they try to land a punch, Clinton comes off as shrill, while Obama can appear condescending.

If Edwards chooses to endorse, his nod would be portrayed not only as a choice for a candidate, but a choice against the other. The visual would be striking: Either two men would gang up on a woman, or two white candidates would take on a minority. If a campaign is considering how to roll out Edwards' endorsement, it would do well to put him on the stump as an entirely positive messenger. Any negativity could seriously blunt his positive impact, and even turn a benefit into a major liability.

On the other hand, Edwards may not decide to make an endorsement until a nominee is determined. Before leaving the race, he secured guarantees from both candidates that they would make solutions to poverty a central part of their campaigns. Given his support among the Democratic base, it is also likely he will play a role in the next Democratic administration. In a race that still looks neck-and-neck, an endorsement could only jeopardize his future. Edwards might calculate that, instead of risking backing the wrong horse, he would be better served by remaining above the fray and an acceptable cabinet member in either administration.