The Securities and Exchange Commission has come out in defence of the Public Accounting Oversight Board against the lawsuit challenging its constitutionality.

The lawsuit, filed in February by the Free Enterprise Fund, a conservative think tank, is being led by Ken Starr, the prosecutor who led the charge on Whitewater and monica Lewinsky. It is step one in the legal moves against Sarbanes-Oxley.

The SEC brief is aimed at refuting the lawsuit's argument that the setup of the PCAOB violated the separation of powers principal under the Constitution as well as its appointments where members of the SEC - as opposed to anyone from the executive, legislative, or judicial branches of government - appoint the PCAOB's members.

The plaintiffs argue that the PCAOB's "inferior officer" need to be appointed by the President, a court, or the head of a federal agency.

Not so, says the SEC, the claims are without foundation because of the SEC's "pervasive oversight authority" and accuses them of making "overblown" assertions.

The SEC move coincides with a brief filed last week where seven former chairmen of the SEC, including William Levitt and William Donaldson seek to protect the PCAOB from the lawsuit which they claim is "little more than thinly disguised attacks on the constitutionality of independent administrative agencies per se."

Still, the CFO.com blog questions whether the SEC is serious or whether it's just going through the motions.