What looks like a tactical change of course puts even more emphasis on Court of Federal Claims' rulingsThe focus of Fannie Mae / Federal National Mortgage Assctn Fnni Me OTCBB:FNMA litigation has narrowed even more, with Bill Ackman's Pershing Square Capital Management filing a notice of voluntary dismissal for its lawsuit in the DC District Court on Friday. This doesn't mean that Ackman has given up the fight, his lawsuit in the Court of Federal Claims under Judge Sweeney is still ongoing, and if you listen to some Fannie Mae bulls, it could even be a smart tactical move. Sign up for our free daily newsletter Fannie Mae – Ackman focuses on Federal Claims Last month, Fannie Mae / Federal National Mortgage Assctn Fnni Me OTCBB:FNMA and Freddie Mac / Federal Home Loan Mortgage Corp OTCBB:FMCC shareholders took a big hit when US District Judge Royce Lamberth threw out Perry Capital's and Fairholme Fund's cases. While it is a major setback, both plaintiffs are appealing and it's only half of the overall argument against government actions regarding the GSEs: the cases in front of Judge Lamberth claim that the government violated the Administrative Procedures Act by overstepping the authority given in HERA, while the cases in front of Judge Sweeney claim that the full income sweep violates the Takings Clause. Ackman's case hadn't yet been thrown out by Judge Lamberth, but it's hard to see what could cause Lamberth to reach a different conclusion for what is nearly an identical case, and Ackman's decision to drop the matter means that he doesn't think the Administrative Procedures Act is going to work out and doesn't want to follow through with a lengthy appeals process. It's not great news for shareholders, but it's not a fundamental shift either.