FEEL THE BURN Fonda, left, has tough love for Lohan.

When Jane Fonda returned to the screen after a 15-year hiatus in 2005’s Monster-in-Law, her character passed out in a plate of tripe. Such ignominies have become par for the course for actresses over a certain age; the toxic Georgia Rule affirms that it’s okay to subject Lindsay Lohan, Fonda’s junior by almost 50 years, to even more noxious humiliation.

By now you’ve heard about the harshly worded letter Lohan received from one of Georgia Rule’s producers, upbraiding her for tardiness and threatening legal action if her unacceptable behavior continued. Lohan made the mea culpa rounds last week, going on Letterman to hail Fonda as “amazing” and thanking her for teaching her to be on time. Fonda plays the Lord-loving martinet of the title, who’s left to take care of granddaughter Rachel (Lohan), a Pound-quoting wild child (crank addiction in the ninth grade, outrageously aggressive sexual behavior, etc.), after her alkie mama, Lilly (Huffman), Georgia’s daughter, dumps her in Idaho.

That Georgia Rule is overstuffed with matriarchal bromides is the least of its problems. When the plot of a movie hinges on whether or not the teenage protagonist is lying about being systematically raped by her stepfather, that film becomes not a rom-com, not a redemption song, not a pleasant Mother’s Day outing, but an odious cultural product. “To forgive is to move forward: Georgia rule,” says Fonda, who, of all the performers trapped in this disaster, maintains the most dignity in her slim-cut Mom jeans. Audience members will surely move on. The film is unforgivable. (Now playing; Click here for venues.) — Melissa Anderson