Note to candidates: If you're going to accuse your opposition of cutting back room deals with a nuclear power company, you probably should make sure no one on your own staff is taking home six-figure paychecks from that same company.

At this point, both Hillary Clinton and Barack Obama probably wish they had never heard of the Exelon Corporation, because new disclosures of money changing hands isn't helping either one of them in the battle for higher ground.

The origins of this spat go back to late 2005, when Exelon disclosed that it's Braidwood nuclear plant in northern Illinois had leaked tritium, a radioactive byproduct of nuclear power, into nearby drinking water wells. The levels did not exceed federal standards, but the incident prompted Obama to introduce legislation that would force nuclear plants to immediately disclose any accidental release of radioactive material.

The bill was revised several time over the objections of environmental groups, who said Obama had replaced mandates with guidance over the reporting of leaks. While the revised legislation made it out of committee, it was shelved before ever coming up for a full Senate vote in 2006.

The issue has re-surfaced in recent weeks in the form of criticism of Obama by Clinton for what she says were suspicious concessions during the rewrite of the bill. "Senator Obama has some questions to answer about his dealings with one of his largest contributors, Exelon, a big nuclear power company," Clinton said last week. "Apparently, he cut some deals behind closed doors to protect them from full disclosure in the nuclear industry."

Why the suspicions? Because Obama senior adviser David Axelrod once worked as a consultant to Exelon, whose employees and executives have donated about $227,000 to various Obama campaigns.

However, as Huffington Post disclosed yesterday, the consulting firm of Clinton chief strategist Mark Penn received a check from Exelon from $230,000 just last week. That payment, for assistance in renewing a nuclear energy license in New Jersey, was invoiced by Penn's firm in December.

So, to recap, that's $227,000 to the Obama campaign and $230,000 to a Clinton big shot. Both sides might want to call this one a wash and keep their mouths shut about who's receiving preferential treatment from whom.