The point of a lawsuit is to establish precedent on executive powers, to reign in a lawless president that is abusing his authority.
His primary job is to faithfully execute the powers of his office, not to rewrite the constitution, rather than defend it.
.Supreme Court rulings..
http://en.m.wikipedia.org/wiki/Signing_statement
The Supreme Court has not squarely addressed the limits of signing statements. Marbury v. Madison (1803) and its progeny are generally considered to have established judicial review as a power of the Court, rather than of the Executive. Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984), established court deference to executive interpretations of a law "if Congress has not directly spoken to the precise question at issue" and if the interpretation is reasonable. This applies only to executive agencies; the President himself is not entitled to Chevron deference. To the extent that a signing statement would nullify part or all of a law, the Court may have addressed the matter in Clinton v. City of New York (1998), which invalidated the line-item veto because it violated bicameralism and presentment.
In Hamdan v. Rumsfeld (2006), the Supreme Court gave no weight to a signing statement in interpreting the Detainee Treatment Act of 2005, according to that case's dissent (which included Justice Alito, a proponent of expanded signing statements when he worked in the Reagan Justice Department — see "Presidential Usage" below).
Presidential usage
The first president to issue a signing statement was James Monroe.[10] Until the 1980s, with some exceptions, signing statements were generally triumphal, rhetorical, or political proclamations and went mostly unannounced. Until Ronald Reagan became President, only 75 statements had been issued; Reagan and his successors George H. W. Bush and Bill Clinton produced 247 signing statements among the three of them.[11] By the end of 2004, George W. Bush had issued 108 signing statements containing 505 constitutional challenges.[11] As of January 30, 2008, he had signed 157 signing statements challenging over 1,100 provisions of federal law.[12]
The upswing in the use of signing statements during the Reagan administration coincides with the writing by Samuel A. Alito — then a staff attorney in the Justice Department's Office of Legal Counsel — of a 1986 memorandum making the case for "interpretive signing statements" as a tool to "increase the power of the Executive to shape the law." Alito proposed adding signing statements to a "reasonable number of bills" as a pilot project, but warned that "Congress is likely to resent the fact that the President will get in the last word on questions of interpretation."[13]