This is not an April Fool’s proposal: The House ethics committee ought to get to work.

Supposedly, it is still investigating — at his request — the multiple tax problems of House Ways and Means Chairman Charlie Rangel (D-N.Y.). We hope to hear about some result of that inquiry one day soon.

But there is lots of other work the committee could be doing, starting with probing the Congressional end of the PMA Group’s lobbying activities. The now-defunct firm’s campaign fundraising practices reportedly are the subject of an FBI investigation, but that does not preclude the committee from investigating PMA’s lavish entertaining of Members and staff over the years, which well could violate past House gift limits.

Rep. Jeff Flake (R-Ariz.) has been pushing in vain for a broader inquiry into PMA’s ties to Rep. John Murtha (D-Pa.) and other House appropriators — specifically, PMA’s hundreds of thousands in campaign contributions per election cycle and hundreds of millions in earmarks obtained for clients.

House Democratic leaders are stoutly resisting any such probe, but Flake has not been willing, either, to file an ethics complaint directly against Murtha. An aggressive — even marginally active — ethics committee could look into this on its own.

Then, there is the matter of Rep. Alan Mollohan’s (D-W.Va.) family charitable foundation, which as Roll Call reported on Monday is actually run by a consortium of small high-tech firms, many of which benefit from Mollohan-sponsored earmarks or government contracts.

Mollohan is not alone in maintaining a favored charity that serves as a magnet for contributions from companies doing business with the government. Murtha has one and so does Rep. James Clyburn (D-S.C.).

There’s no question that the charities do good works — mainly, distributing college scholarship money to students in their districts.

But ethical questions are involved: Are these entities vehicles for businesses to curry favor with the Member? And are they essentially pass-throughs whereby beneficiaries of Member largess return the favor by helping the Member politically?

Since 2000, Mollohan’s family foundation has provided more than $750,000 in scholarship money and donations to charities in his district. The Murtha-backed Challenge Program annually hands out hundreds of $250 checks to high school students. No doubt the recipients are grateful. And so are their parents, all voters.

It’s a quandary: Members like Murtha and Mollohan undoubtedly have helped their districts economically by using their power to steer government money to businesses in their districts. The businesses are grateful and support the Member politically — with political donations and charitable contributions.

But when does this exchange of favors cross the line into influence-peddling or even bribery? There’s enough smoke rising out of Murtha and Mollohan’s office doors for the Committee on Standards of Official Conduct committee to see whether there’s a fire inside.