For Democratic U.S. Senate candidate Cynthia Dill it must have looked like a classic good news/bad news joke.

Good news? You are finally getting some support from the party in D.C.. Bad news? It’s not your party.

And it’s no joke. A political action committee with ties to the Republican Governors Association had produced an ad encouraging Democrats to vote for Dill and not independant Angus King.

This is an act of political cynicism so low it should backfire completely and make everyone who ever thought it was a good idea sorry they came into work that day.

For those who don’t get what the problem is, here’s what’s wrong:

A positive ad that tells people to vote for your candidate is good. A negative ad that tells people to vote against your opponent is OK if the charge is factual.

But an ad that tries to take votes away from one opponent by pretending to support a weaker one is dishonest and shameful. It’s an attempt to manipulate voters and game the system and it should not be rewarded at the polls.

It’s clear what the group is up to. Gov. LePage was elected with only 38 percent of the vote in 2010 because a Democrat and an independent split most of the rest of the vote. In order for there to be a similar result in this year’s Senate race for Republican Charlie Summers, Dill needs to be more competitive than she has shown so far in public polls.

But this ad that purports to help Dill in her race will ultimately hurt her, because it tells Democratic voters that Republicans want her to do well in order for them to win. And it won’t help Summers either, because even though he says he has nothing to do with this move, he is its intended beneficiary.

The only candidate this could possibly help is King himself, who has based his whole campaign on the emptiness of partisan politics, where both sides are more interested in winning elections than solving problems.

These political pros couldn’t have helped their opponent more if they had gone out and bought ads telling Mainers to vote for King.

But we shouldn’t joke about that — in this environment, someone might be crazy enough to try it.