BARBRA STREISAND‘s fanatical support of the CBS movie smearing President Ronald Reagan wasn’t just politics — it was personal!

The ENQUIRER went behind the scandal and learned that Streisand, one of Hollywood’s most powerful liberals, defended the unflattering and inaccurate portrayal of Reagan, played by her husband James Brolin, because she hates the former Republican President for what she perceives was his failure to combat AIDS.

And her vendetta was only made deeper by the heartbreaking fact that her openly gay son Jason, 37, has contracted the deadly disease, sources tell The ENQUIRER.

“Barbra is furious with Reagan because she felt he was not attentive to the needs of HIV and AIDS patients and didn’t give enough money towards research,” a close Streisand family friend told The ENQUIRER.

“This has always been important to Barbra but it became very close to her heart after her only son Jason was stricken with the deadly AIDS virus three years ago.

“She is not obsessed for the sake of politics, this is deeply personal.”

Streisand vehemently denies having anything to do with the script, which falsely had Reagan calling himself “the Antichrist” and saying that gays deserved AIDS. She also insists that she never told Brolin how to play Reagan, now 92, and in the final stages of Alzheimer’s disease.

But The ENQUIRER has learned the singer has worked before with the producers — Craig Zadan and Neil Meron, who are known for their gay advocacy projects and remakes of musicals, including the Oscar-winning movie “Chicago.” Records obtained by The ENQUIRER show Streisand has worked on at least three telefilms with the two producers since 1995. And she spent four hours on the set of “The Reagans” during filming.

“Do you honestly think James Brolin would have been able to work on this film and Barbra didn’t know anything about it?” declared the Streisand family friend. “Get real.

“There is absolutely no way Barbra didn’t see the script before production started.”

Sources say the singer’s bias against Reagan and his devoted wife Nancy became even more obvious after CBS boss Les Moonves decided the movie was unsalvageable — even after 18 corrections had been made — and moved the miniseries to Showtime. Streisand screamed “censorship” and wrote a scathing attack against conservatives on her Web site.

Observers said it was a shrill response from someone who supposedly had nothing to do with the movie. And her defense of the First Amendment struck many as hypocritical since she once sued a photographer for $10 million — simply for taking aerial photos of her house and displaying them on his Web site.

“Barbra Streisand wants it both ways,” Michael Paranzino, a former Republican congressional staffer who started the Web site in opposition to the new miniseries, told The ENQUIRER.

“On the one hand she’s posted a statement saying, look, I only visited the movie set for four hours and here I am being portrayed as a person being deeply involved in it.

“And yet here she is posting another statement now deploring this — and I’m paraphrasing — as an end of artistic freedom.”

Streisand says producers bowed to pressure from the right.

Sources told The ENQUIRER Nancy Reagan, 82, did send a letter to CBS — but only because she was desperate to stop lies from being spread about her husband.

“Nancy’s exhausted from nine years of nursing a man who now doesn’t even recognize her,” said a source close to the former First Lady. “She just couldn’t believe the producers would put out such a smear when he was on his deathbed.”

Streisand hates Reagan so much it clouds her judgment, insiders insist. “There is at least a 20-year record of Barbra Streisand’s hostility to Ronald Reagan. That’s a fact,” Paranzino told The ENQUIRER.

Longtime Reagan pal Merv Griffin told The ENQUIRER: “Barbra is blinded by her hatred of this wonderful, caring man.”

In 1992 she said she would “never forgive” Reagan for his stance on AIDS research and education.

In a 1999 interview Streisand declared: “The Reagan years legitimized bigotry. AIDS . . . was dismissed as a gay disease with an official homophobic wink, implying that those deaths did not matter because of who was involved.”

That sounds suspiciously like the worst lie in the movie script — when Brolin, as Reagan, says people with AIDS deserve what they get, say insiders.

“It’s atrocious, it’s offensive — and he never said it,” declared Paranzino. “Ronald Reagan was not a homophobe.”

Reagan’s daughter Patti Davis quickly came out in defense of her dad saying he was open-minded about actor Rock Hudson’s homosexuality. And even Hudson’s former lover Marc Christian defended Reagan saying the former President was very warm and supportive of Hudson during his AIDS illness.

Jeff Wald, who is Streisand’s friend and Brolin’s manager, told The ENQUIRER Streisand’s feelings about Reagan are irrelevant and had nothing to do with the tone of the movie.

“Barbra is far removed from interfering in this thing — no matter what people are saying,” he said. “She was on the set up in Montreal — but for four hours only.

“She did not read the script. They never discussed it!

“He didn’t even rehearse at the house. You know where he rehearses? In the car! Barbra heard none of his dialogue till that day she was on the set.”

But in a second interview with The ENQUIRER, Wald admitted that Streisand had worked with the producers in the past.

Paranzino added: “Maybe it’s just one of those amazing Hollywood coincidences where you have the very vocal Barbra Streisand, her spouse, the actors, the writers, the directors all coming from the left politically, all coming together in this one brew,” he said.

“And that is why CBS found themselves just three weeks out, realizing that they had a hatchet job on their hands.”