Insurer American International Group Inc has asked a court to block Maurice "Hank" Greenberg's efforts to sue the U.S. government on AIG's behalf, saying its former CEO has not proven he should have the right to do so. Earlier this year, AIG drew sharp criticism from members of Congress and an outraged public when the firm considered the possibility of joining Greenberg's lawsuit, which challenges the terms of the insurer's $182.3 billion bailout by the federal government in 2008. AIG said Greenberg had forced its hand in even deliberating the prospect, but that ultimately it did not want to sue anyway amid a public backlash. Absent AIG's participation, Greenberg is pursuing a derivative claim, seeking to sue the U.S. government on AIG's behalf over the terms of the $182.3 billion rescue. Greenberg and his company Starr International, which owned 12 percent of AIG before the rescue, are also suing the government directly.