The State Elections Board dealt Republican gubernatorial candidate Mark Green a blow two weeks ago when it ruled he could not transfer $467,844 in campaign contributions from his federal campaign fund into his state fund.

The funds were transferred just one day before the Elections Board enacted a rule prohibiting donations from unregistered out-of-state political action committees, but the rule was applied retroactively to deem the transaction invalid.

Seeking to capitalize on the controversial decision, Democratic incumbent Gov. Jim Doyle has since launched a television advertisement accusing Mr. Green of "breaking the law" in moving the cash to his state account.

We recognize that negative advertisements have long been a staple of political campaigns, and they can be expected to be plentiful in a tight contest like the current gubernatorial race.

But Mr. Doyle's recent offering sets the bar low, and the ad does little to display a commitment to ethical campaigning.

To say that Mr. Green flagrantly and intentionally disregarded state law in transferring the money, as Mr. Doyle's ad does, is disingenuous at best.

The circumstances of the transfer are questionable, but so is the Elections Board's decision to apply the new rule retroactively. An accusation based so purely in the semantics of applying a new rule surely doesn't carry much weight — but, then again, neither does any accusation in an advertisement utilizing cheap attacks to sway voters.

Ultimately, voters will decide how much mudslinging is appropriate, and this board hopes candidates will take that into consideration when planning the remainder of their campaigns.

Editorial board opinions are crafted independently of news coverage.