NEW YORK — Showtime has greenlit production on the original telefilm “The Last Debate,” a political drama based on the novel by PBS’ Jim Lehrer.

Peter Gallagher (“American Beauty”), TV vet James Garner and Tony winner Audra McDonald (“Annie”) will star in the telepic, which tells the fictional story of four journalists who change the course of American history by throwing a presidential debate to the candidate they think should be elected.

John Badham will direct from a script by Jon Maas, who also will produce. Lehrer will serve as a consultant.

Exec produced by Tony and Ridley Scott’s Scott Free Prods. and Diane Minter (“Where the Heart Is”), “Debate” will begin production in Toronto in late June and is expected to premiere on the pay cabler in the fourth quarter of 2000.

Telepic will be distributed by Paramount Network Television.