A sergeant will be discharged for criticizing President Barack Obama on Facebook in a case that called into question the Pentagon’s policies about social media and its limits on the speech of active duty military personnel, the Marine Corps said Wednesday.

Sgt. Gary Stein will get an other-than-honorable discharge and lose most of his benefits for violating the policies, the Corps said.

The San Diego-area Marine who has served nearly 10 years in the Corps said he was disappointed by the decision. He has argued that he was exercising his free-speech rights.

“I love the Marine Corps, I love my job. I wish it wouldn’t have gone this way. I’m having a hard time seeing how 15 words on Facebook could have ruined my nine-year career,’’ he told The Associated Press.

Gary Kreep, an attorney for Stein, said he would pursue administrative appeals within the Marine Corps but anticipates the effort will be denied. He said he planned to file an amended complaint in federal court.

“As long as he wants to pursue this, we will be supporting him,’’ said Kreep, who is executive director of the United States Justice Foundation, an advocacy group.

The Marines acted after saying Stein stated March 1 on a Facebook page used by Marine meterologists, “Screw Obama and I will not follow all orders from him.’’ Stein later clarified that statement saying he would not follow unlawful orders.

During a hearing, a military prosecutor submitted screen grabs of Stein’s postings on one Facebook page he created called Armed Forces Tea Party _ a reference to the conservative Tea Party movement _ which the prosecutor said included the image of Obama on a “Jackass’’ movie poster. Stein also superimposed Obama’s image on a poster for “The Incredibles’’ movie that he changed to “The Horribles,’’ military prosecutor Capt. John Torresala said.

Brig. Gen. Daniel Yoo, the commanding general of the Marine Corps Recruit Depot San Diego, gave no explanation for the decision in a brief statement.

At the hearing this month at Camp Pendleton, Torresala argued that Stein’s behavior repeatedly violated Pentagon policy and should be dismissed after he ignored warnings from his superiors about his postings.

A federal judge previously denied a request to block military discharge proceedings against Stein. (AP)