Less than a week after the Academy of Motion Picture Arts and Sciences publicly kicked out Bill Cosby and  Roman Polanski from its membership, the Oscar winning director says he’ll take the group to court unless he’s reinstated or gets to defend himself.

“I am writing this letter to you to avoid unnecessary litigation,” said Polanski’s attorney Harland Braun in a letter sent to AMPAS president John Bailey today (read it here). “Mr. Polanski has a right to go to court and require your organization to follow its own procedures, as well as California law,” the lawyer adds, detailing his previous statements that the Movie Academy broke its own Standards of Conduct rules when the board of governors voted last week to boot Polanski and Cosby for misconduct.

Having won the Best Director Oscar in 2003 for The Pianist, Polanski has been in self-imposed exile in Europe since he fled the U.S. 40 years ago after being convicted in 1978 of raping a then 13-year-old girl. With his French citizenship as a protective shield and the support of a number of prominent producers, studio bosses and talent over the years,  the Polish-born filmmaker has successfully fended off various disorganized attempts by American officials to bring him back to face justice.

Over the past year, Braun has headed an unsuccessful effort to establish that his client was actually the victim due to court misconduct and political corruption decades ago and more recently. To that end, Braun has advocated that 84-year old Polanski should be allowed to return Stateside and to work in Hollywood without fear of further punishment. In January, the L.A. Country District Attorney’s office decided not to bring charges against Polanski over the alleged rape of a 10-year old in 1975 as the statute of limitations had expired.

Now the lawyer is preparing to fight a new battle for his client on a new front if the Movie Academy doesn’t reconsider its announcement of April 26.

“The only proper solution would be for your organization to rescind its illegal expulsion of Mr. Polanski and follow its own Standards of Conduct by giving Mr. Polanski reasonable notice of the charges against him and a fair hearing to present his position with respect to any proposed expulsion,” Braun wrote to Bailey Tuesday. “We are not here contesting the merits of the expulsion decision, but rather your organization’s blatant disregard of its own Standards of Conduct, as well as its violations of the standards required by California Corporations Code,” the LA-based attorney also points out in the 2-page correspondence.

Previously having cited Polanski and Braun as spotlighting the wrong set of rules that saw the director tossed, AMPAS did not respond today to request for comment on this latest move by the litigious director … yet.

Having been found guilty on April 26 of three counts of aggravated indecent assault for the January 2004 sexual assault of Andrea Constand in a retrial, much accused 80-year old Cosby has not made any noise about trying to rejoin the Movie Academy or any of the many other organizations that have kicked him out or stripped him of honors over the past two years.