Will it be the whip or the quips? Screenwriter Jeff Nathanson’s labors on the new installments in the “Rush Hour” and Indiana Jones series have taken more turns than, well, an Indiana Jones plotline. But, for now at least, Indy is on the front burner. Just as Chris Tucker did another about-face and failed to sign a $20 million deal that would fast-track New Line’s “Rush Hour 3,” Nathanson’s draft for “Indy 4” has apparently met with the approval of George Lucas and Steven Spielberg. But before Paramount can dust off Indy’s signature Stetson and bullwhip, Harrison Ford — the third key member of the Indy triumvirate — has to sign off on the script, and he hasn’t yet read Nathanson’s draft. An earlier effort by Frank Darabont failed to pass muster with the trio. So far, that leaves “Rush Hour 3” on Nathanson’s back burner, but things could change yet again. Nathanson had expected that film to be his next assignment, and New Line hoped it would anchor its summer 2006 slate. But the project came to a halt in recent weeks when Tucker did not sign his deal. New Line had made an agreement with Tucker, Jackie Chan and director Brett Ratner to pay Nathanson — who penned “Rush Hour 2” — $250,000 to write a treatment. If they liked Nathanson’s pitch, each would waive script approval. But Tucker changed his mind at the last moment, and New Line refused to cut a seven-figure check to Nathanson unless it knew the film would get made.