John Ensign’s resignation was two-fold: a favor to Rep. Dean Heller, who will probably get his seat and also a leg up in the 2012 Senate race from being the incumbent; and a way to avoid a budding Senate Ethics Committee investigation. The Justice Department and the FEC closed their investigations against Ensign, but the Ethics Committee had an ongoing probe. And, the New York Times has learned that Ensign was scheduled for testimony:

Senator John Ensign’s resignation letter allows him to leave office just one day before he was to have to answer questions under oath about whether a $96,000 payment to the family of his former lover was illegal, designed to keep the affair from becoming public, according to people familiar with an investigation of Mr. Ensign’s activities.

That formal testimony scheduled for May 4 was the final step as Senate investigators prepared for what were almost certain to be Senate ethics charges against Mr. Ensign, Republican of Nevada. Mr. Ensign’s resignation is effective May 3.

Incidentally, while Ensign gets to avoid that testimony, he will not be able to avoid the final ruling from the Ethics Committee. They plan to issue a statement – on a bipartisan basis, with the support of both Democratic Chair Barbara Boxer and Republican Vice Chair Johnny Isakson – detailing the findings of the nearly 2-year investigation. They say that they have uncovered evidence of wrongdoing and that Ensign “made the appropriate decision.”

The $96,000 payoff was a particular concern of the investigation. Delivered in installments to fall under disclosure limits, it was clearly an off-the-books severance payment and a potential violation of campaign finance laws, since Hampton was an employee of Ensign’s political campaign and the payment needed to be disclosed.

The FEC is hopelessly broken at this stage, but the Senate Ethics Committee appears to have taken its role seriously, and they aren’t going to bury the report just because Ensign would rather run and hide than face up to his actions. They cannot fully disclose the materials gathered over the course of the investigation, but the public statement has the potential to be damning. And they could choose to make a referral to the Justice Department for criminal charges as well. I’d be surprised if it came to that, but Ensign didn’t resign just to be nice to Dean Heller.