Santa isn’t put on trial in “The Santa Clause,” but he does get chased by the cops. Tim Allen, of the ABC hit “Home Improvement,” makes his movie debut as a divorced toy-company executive, Scott Calvin. On Christmas Eve, Calvin grudgingly fills in for Santa when the big guy takes a tumble off his roof. Then he learns he’s got the job for life, and suddenly he’s sprouting a white beard and putting on 45 pounds in a week. Calvin’s ex-wife (Wendy Crewson) and her new husband (Judge Reinhold) think he’s crazy and dangerous, but his son (Eric Lloyd) thinks he’s a hero. “The Clause,” directed by John Pasquin, makes the same musty point as “Miracle”–namely, you gotta believe. Allen is likable (if you like him), and he pulls off plenty of cute bits and sarcastic one-liners. Still, under all the gift-sapping, this is really a story about an estranged father who loses visitation rights, kidnaps his son and becomes the subject of a manhunt. Which may or may not put you in the holiday spirit. “Mrs. Doubtfire” got away with this sort of broken-home hand-wringing because it could be helplessly funny. But “The Clause” is clunky and ramshackle. Like “Miracle,” it never really takes off–and true believers are right to expect more. Heck, even reindeers can fly.