De Niro squanders his movie legacy in juvenile family comedy 'The War With Grandpa'

“The War With Grandpa” - ★ ★

Inconceivable.

Yep, that's the word.

During the 1970s and 1980s, it would have been inconceivable that Robert De Niro, the most incendiary, unpredictable and dangerous actor of his generation, would wind up trapped in this vortex of conventional, innocuous stock characters and C-grade craftsmanship.

“The War With Grandpa” demonstrates how the best of intentions can easily be neutralized by an overuse of clumsy stunt doubles and a screenplay that panders to kids instead of elevating or challenging them.

Here, De Niro plays Ed, a crusty senior citizen still mourning the loss of his wife. He's a fuddy duddy technophobe who can't wrangle those newfangled things call smartphones, iPads and laptops.

His advancing years become a concern for his daughter Sally (Uma Thurman) and her husband Arthur (Rob Riggle).

So, they push him into coming to live with them by pushing their tweener son Peter (a winning Oakes Fegley) out of his spacious bedroom into a cramped attic.

He doesn't like that.

He sends Grandpa a note demanding he relinquish the bedroom to its rightful owner. Grandpa diplomatically ignores it, prompting Peter to declare a merry war of tricks and booby traps against this invader.

“The War With Grandpa,” directed by Tim Hill as if he were making a Dean Jones comedy for Walt Disney during the 1970s, has the feel of a rushed production that missed the memo about old guys ogling women in exercise attire: It still isn't funny.

Thurman, a veteran of Quentin Tarantino's sharply edged cinema, tries to pump some vitality into her tired, patient mom/daughter character.

Riggle gets stuck with a standard-issue doofus dad. He not only can't tell the difference between Kmart and Walmart, but also he's too mealy-mouthed to confront Ed for disrespectfully calling him “Arty” instead of his preferred “Arthur.”

(Near the end, Ed finally calls him Arthur and adds, “Did you notice I called you Arthur?”

Yes, we all did. But the filmmakers don't trust we were engaged enough to notice it the first time.)

“The War With Grandpa” features a stellar supporting cast with Christopher Walken and Cheech Marin as Ed's funny buds and the classy Jane Seymour as Ed's safely platonic romantic interest.

On the upside, De Niro and Fegley share a beguiling chemistry that minimally compensates for the rote portions of this instantly forgettable comedy, one that doesn't forget the obligatory staple of kid movies, here a painful dodgeball to the crotch.

• • •

Starring: Oakes Fegley, Robert De Niro, Jane Seymour, Uma Thurman, Christopher Walken, Cheech Marin

Directed by: Tim Hill

Other: A 101 Studios release. Rated PG. 94 minutes