The issue focused on federal election law. Lawmakers had previously blocked enforcement of laws requiring political parties to submit financial statements.

On Tuesday, Attorney General Eric Holder sent a letter to lawyers at several legal organizations asking them to investigate whether Justice Department prosecutors were illegally prosecuting civil rights attorneys and seeking evidence that illegal prosecution was related to criminal prosecutions.

In one lawsuit filed by attorney Brian Singerman in 2011, federal prosecutors accused him of failing to properly file reports as required under state law. They say he failed to