The stench of scandal surrounding Members of Congress and PMA, the now-defunct lobbying firm raided by federal agents in 2008, was so acrid that the House last year passed a resolution asking the House ethics committee whether it was conducting an investigation.

Oh, yes, said the Committee on Standards of Official Conduct. It claimed it had opened a probe in the spring of 2009. On Feb. 26, the committee cleared all Members of any wrongdoing.

Except now it develops that the committee apparently did little or no investigating at all. If that’s the case, a stench of deception now surrounds the ethics committee.

For nearly three years, Roll Call and other news organizations have reported on the tens of millions of dollars in earmarks secured for PMA clients, chiefly by members of the House Appropriations Subcommittee on Defense, and the millions of campaign contributions donated by those clients.

Last December, the new Office of Congressional Ethics delivered exhaustive reports, 30 to 40 pages long, on seven Members of the Defense panel, clearing five but referring two for further investigation by the ethics committee.

In clearing all seven, the committee asserted it had reviewed nearly 250,000 pages of documents and conducted interviews with “numerous witnesses.” But Roll Call contacted numerous firms and Member offices that would have been logical sources of information for the committee — and found that not a single one had been contacted or asked for documents.

Moreover, the OCE, created in 2008, is only empowered to look into allegations occurring after its establishment — leaving years of PMA earmark-cadging to be probed.

Just as one example, Roll Call reported in 2007 that one member of the Defense panel, Rep. Peter Visclosky (D-Ind.), had established a technology center in his district with 14 business tenants — but only the five PMA clients got earmarks sponsored by Visclosky.

Visclosky was one of those referred by the OCE to the ethics committee, pointing to documents indicating that companies believed their campaign contributions were buying them access and assistance with earmarks.

The ethics committee cleared Visclosky. It did interview two of his staffers, but there’s no indication that it interviewed him. His office is mum.

Also, there are several other Members, not on the Defense panel, who might reasonably have been contacted about PMA activities. None of them were, their offices said.

So what can we make of this? For sure, proving what much of the public suspects — that Members trade earmarks for campaign money, quid pro quo — is very difficult. But, it appears, the ethics committee didn’t even try.

It said it did so, but we suspect it merely reviewed the OCE’s reports, found no provable wrongdoing and cleared everyone involved. We’d call that a whitewash.

The smell simply will not go away, however. We suggest that those who originally demanded that ethics investigate PMA now demand that a special probe be undertaken to investigate the ethics committee.