As days grow shorter and weather turns colder, political campaigns lose their light and crank the heat.

It’s happening here, as complaints of intrusive “robo-calls” spring up. They are a “be careful what you wish for” corollary for becoming a presidential battleground territory.

The robo-calls, from the campaign of Sen. John McCain and the Republican National Committee, highlight the relationship between Sen. Barack Obama and 1960s radical William Ayers, a strong McCain campaign talking point.

Such tactics are pro forma for the waning days of a hard-fought campaign. Seasoned political observers note that positive messaging only works for so long. To really motivate voters when it counts, nothing works finer than some old-fashioned anger.

Maybe so. But while this is presented like a regrettable human failing, it’s more likely ready-made rationale for smacking a political opponent in the teeth. This is a bipartisan problem – Obama and McCain are both guilty of it – that takes guts to repudiate.

Sen. Susan Collins, embroiled in her own re-election battle with Rep. Tom Allen, has repudiated the McCain robo-calls, saying “they have no place in Maine politics” and should “stop immediately.”

Sen. McCain’s campaign has declined to do so.

Collins deserves credit for her principled stance. She’s quite right; from our anecdotal experience, these calls are angering and frustrating Democrats and Republicans alike, who are sick of political attacks in these trying economic times and desirous of substance. It’s not what they’re getting, at least on their phone lines and voicemail.

One of the finer traits of the Collins-Allen race has been their efforts to reject political tricks and third-party attacks. It hasn’t always worked – in politics, what does – but the attempts reflected sentiments of Maine voters.

Which is why it’s so quizzical that the McCain campaign won’t heed Collins’ warning. Maine’s junior senator is not only co-chairwoman of McCain’s campaign in Maine, but is also considered one of his allies in the U.S. Senate.

More than that, though, she’s from the district his campaign is desperately trying to win. And, maybe most important, she’s running double-digits ahead of Allen in many polls, despite national troubles for many Republicans.

McCain needs and wants Maine votes. The campaign has delivered visits from two Palins and a McCain daughter in the past two weeks to try to secure them. But when the candidate who knows the 2nd District best and what it takes to win there, speaks up, the campaign doesn’t listen.

In the long run, this could be shortsighted. Sen. Collins has bluntly stated the calls “don’t serve John McCain well.”

We think she knows what she’s talking about.