Chris Matthews did a segment on Rove's group with Dan Froomkin and Joe Conason last month where they were looking at whether the IRS might go after Rove's group for the abuse of their tax status.

The Huffington Post has more on the dust up between Rove and the Obama campaign's attorney here: Bob Bauer, Obama Campaign's Top Lawyer, Demands Retraction From Karl Rove:

The Obama campaign's top lawyer fired off a letter to Karl Rove Thursday, demanding a retraction of a "mystifying" comment Rove made and raising questions about his upcoming appearance at a Mitt Romney campaign event.

The letter is the second that Bob Bauer has sent to Rove this week. The first argued that Rove could no longer insist that his advocacy group, Crossroads GPS, was policy oriented -- a distinction that allowed it to shield the names of its donors. The follow-up letter, obtained by The Huffington Post, makes that same point, arguing that there is no "social welfare" component to the group's operations.

But it also challenges Rove in more direct terms. Bauer hints that Rove, the chief strategist to former President George W. Bush, is colluding with Romney, the presumptive GOP presidential nominee, by homing in on Rove's presence at a Romney retreat in Utah this upcoming weekend. He also expands the scope of his complaint to Rove's role with American Crossroads, the super PAC arm of Crossroads GPS. [...]

The letter also picks up on an exchange between the two that was escalated Wednesday night when Rove accused Bauer of having a political vendetta against him that was rooted in earlier legal conflict.

In an appearance on Fox News, Rove insisted that Bauer had represented Dana Jill Simpson, the former Republican operative in Alabama who served as a whistleblower against Rove and others in the case of former Gov. Don Siegelman.

"This is the kind of guy Bob Bauer is," Rove told Fox News host Greta Van Susteren. "I know what he’s doing. It is not going to change us in one way shape or form from doing exactly what we’re entitled to do under the law."

But it turns out that Bauer never represented Simpson. Nor, he wrote in the Thursday letter, did he have "anything at all to do with her allegations about you or any appearance by her on 60 Minutes."

"The identity of her lawyer is a matter of public record – a lawyer I have also never met," Bauer added. "Please promptly correct these remarks on the record." Read on...