This may not be great news for Donald Trump, but it’s almost certainly worse for Rudy Giuliani. Fresh off his airport arrest, Lev Parnas has now signaled to the House committees investigating Ukraine-Gate that he would be willing to cooperate. His attorneys told Reuters and other media that Parnas won’t go so far as to incriminate himself, but that doesn’t mean he’ll be shy about dishing on others:

Lev Parnas, an indicted Ukrainian-American businessman who has ties to President Donald Trump’s personal lawyer, Rudy Giuliani, is now prepared to comply with requests for records and testimony from congressional impeachment investigators, his lawyer told Reuters on Monday.

Parnas, who helped Giuliani look for dirt on Trump’s political rival, former Vice President Joe Biden, is a key figure in the impeachment inquiry that is examining whether Trump abused his office for personal political gain.

His apparent decision to work with the congressional committees represents a change of heart. Parnas rebuffed a request from three House of Representatives committees last month to provide documents and testimony.

It’s not a complete change of heart. Parnas’ attorneys made clear the limit of his cooperation:

“We will honor and not avoid the committee’s requests to the extent they are legally proper, while scrupulously protecting Mr. Parnas’ privileges including that of the Fifth Amendment,” said the lawyer, Joseph Bondy, referring to his client’s constitutional right to avoid self-incrimination.

In any other context, that would be a very non-subtle hint for an immunity offer. However, that’s a fraught prospect for the House committees working on this probe. As Josh Gerstein notes at Politico, it would require a two-thirds vote to approve, which means some Republicans would have to come along. The Department of Justice can also delay that application for immunity and could conceivably fight it. Thirty years ago, such deals let Oliver North and John Poindexter off the hook for prosecution in Iran-Contra, backfiring on Congress after that scandal faded away without any action against Ronald Reagan.

Besides, it’s not all that clear what Parnas would dig up on Trump anyway, since it seems very unlikely that Trump would have engaged with him directly at all. Trump has already denied having anything other than casual contact with Parnas, which supposedly has upset the indictee:

Bondy said Parnas was “very upset” when Trump denied any association with him after word broke that he and Fruman were arrested.

“Imagine just the lay of the land: you give a bunch of money, you’re sitting with him at apparently intimate dinners, you’re seen waving at him at fundraisers and him waving back, you’re somehow recruited by Rudy Giuliani and after all that — spending a heck of a lot of money on Rudy Giuliani traveling or whatever — you’re sitting in a prison cell waiting to be bailed out and you learn the president has completely distanced himself from you. Of course, you’d be upset,” Bondy said.

If all Parnas has on Trump is some mutual waving at fundraisers, good luck with that. Parnas might have some dirt on Giuliani, however, which is where this testimony might be valuable. If they can find evidence that Giuliani committed crimes, then they could pressure him to testify against Trump.

However, all of that is extremely unlikely for several reasons. First, Parnas’ attorneys are making it clear that Parnas won’t implicate himself, which will make it tough to implicate Giuliani. If Parnas tries to solve that by offering  intentionally misleading testimony through omission, the DoJ will jump all over Parnas, and his attorneys know that. Even if Parnas spilled his guts, the House would have to find a statutory crime committed by a man whose also a very cagy attorney himself, and then convince the DoJ to prosecute Giuliani over it. The testimony of an accomplice isn’t enough to go to trial, even if it were reliable and there’s a statutory violation worth prosecuting. So far, despite weeks of testimony, the House committees haven’t found a single statutory violation in Ukraine-Gate by anyone. (Parnas’ indictment is over other issues.)

Without a doubt, Parnas’ testimony should prove entertaining, if not enlightening. Giuliani might be a cagy attorney in some contexts, but he’s been a loose cannon on the diplomatic front. The worst that Parnas might end up delivering is some embarrassing anecdotes about Giuliani’s antics in Ukraine, and that’s if the House wants to wait long enough to deal with Parnas’ other legal issues. At this point, they might be better advised to push forward with an impeachment vote without his cooperation.