A byproduct of running one of America’s most-watched campaigns for the U.S. Senate is, all of a sudden, having a lot of friends you wished you didn’t.

This is Rep. Tom Allen’s quandary, and the genesis of his surprising announcement – or declaration, rather – on Monday toward outside parties interested in tearing down his opponent, Sen. Susan Collins: your uninvited assistance is now entirely unwelcome.

“I want to make it clear to these outside groupsthat if they plan to attack Sen. Susan Collins, don’t,” says Allen.

Of course, this could be interpreted as Allen calling off the hounds after they’ve smelled the rabbit. Independent political groups, like MoveOn.org and others, have been pushing Allen’s candidacy at Collins’ expense for months.

Allen has also been criticized for his financial support from MoveOn members, a charge he considers specious, because of MoveOn’s membership criteria. “All it takes is giving them an e-mail,” he says.

But the figures are anything but specious – MoveOn members raised $250,000 for Allen last year, which he then touted in an interview as “you [making] a difference.”

“Frankly, I’m going to be relying on the netroots,” Allen said in a July 27, 2007 interview with Jonathan Singer, of mydd.com. “Because it alters the whole balance of power here in Washington and I don’t have to depend on oil companies and pharmaceutical companies and insurance companies to raise money for a campaign.”

It is also arguable that Allen’s political capital has increased with outside influences. MoveOn, for example, pestered Collins so incessantly she responded with campaign videos of her own, which used powerful MoveOn.org rhetoric as a fundraising overture to potential donors.

“The video is intended to alert potential contributors that MoveOn.org and its allies have landed in Maine, and we are asking for their help in fighting back,” Collins campaign manager, Steve Abbot, told the Portland Press Herald in February, after her counter-video started circulating.

While interesting, such outside intervention is only a sideshow. Allowing others to run roughshod with their own agendas does hurt this race. The voters’ decision shouldn’t be influenced by others’ desires to tilt the Senate’s demographics one way or the other.

Allen is right to try to return this campaign to the people who will decide the election.

That is idyllic thinking, though.

Truth is, Allen cannot control these outside groups. He admits a preemptive denunciation of future attacks on Collins is the most “dramatic” step he can take. But harsh words wilt against those willing to take bold actions.

The reason these groups are so powerful is they represent strong constituencies, who support their guerrilla tactics.

Through this pledge, Allen may be trying to distance himself from some of his more vicious supporters, who could do his campaign more harm than good. He is right in asking them to stop.

But what he wants doesn’t matter.

What matters is whether they listen.