The Pooch and the Pauper (2000)

Sinopsis

The bulldog Liberty (who's thoughts we're able to hear) is the "First Dog of the USA", i.e. the president's dog. As such he has a lot of representative duties, but also many privileges which made him snobby and condescending towards other dogs. But one day when the young Nataniel takes him for a walk, he's mixed up with the stray dog Moocher who looks like his identical twin. Henceforth Moocher takes Liberty's place in the White House. From now on a different spirit reigns in the White House