We don’t know exactly who the Caremi Partners are, where they’re from, what they want or why they’re spending $150,000 to defeat the Forest Compact. Neither, apparently, does Jonathan Carter, but he should find out.

Carter’s attempt to present his anti-Compact campaign as a squeaky-clean, grassroots uprising of just plain folk received a bloody nose Tuesday when it was revealed he cashed a check for 150 grand from Caremi Partners Ltd. to buy radio and TV ads. Nothing wrong with that — it takes money to get on the air. What is wrong is that the jumbo donation did not show up on the September disclosure form submitted to the state, despite strong evidence it was at least promised before the end of the month.

Even more wrong is that Carter can’t, or won’t, say what Caremi Partners is, other than to offer that it includes real-estate speculators registered as a corporation in Delaware. That helps a lot, given that any corporation with a clue about the tax code is chartered in Delaware. Reportorial sleuthing has tracked Caremi from a pile of Delaware paperwork to a New York lawyer to a street address in Greenwich, Conn., but it’s a dead end after that.

Such sleuthing should not be necessary in Maine. Candidates and leaders of political causes have a moral obligation not to accept large contributions unless they are willing to say who’s giving. The public has a right to know who is trying to sway it.

Then there is the legal obligation. Maine election law says contributions must be reported during the month they were received or pledged. Carter, who had $184 in his anti-Compact bank account at the end of September, says he hadn’t an inkling about the windfall until Caremi came through on Oct. 8 or 9. The ads started running on the 10th. One or two days to put together and buy time for a major media blitz — that’s fast.

On the other hand, Matthew Manahan, attorney for the pro-Compact side, says several television stations tell him Carter began scheduling $100,000 worth of air time back in September. If Carter didn’t know the Caremi check was in the mail, he must have had a real good feeling about that week’s Megabucks.

Yes, the pro-Compact side has raised a ton more money, nearly $1.5 million. But people in Maine know what Bowater-Great Northern is. Ditto Champion, Georgia-Pacific, International Paper, Forestry Management and Trucking, Tracker Guide Service. There’s no guesswork, there’s not a mysterious Caremi in the bunch. And it’s all reported in excruciating detail, right down to the $100 in-kind contribution from Manahan’s law firm, which provided a room for a meeting.

Carter responds with the Compact backers not being able to discredit the message so they’re trying to discredit the messenger, adding, “We have followed the letter of the law.” The letter would be nice, but the spirit would be even better.