I accidentally saw this movie recently.
The Pacifier, Starring Vin Diesel, is another one of those, "Tough guys is forced to watch a bunch of crazy lovable kid" films. In the grand tradition of Kindergarten Cop and The Game Plan.
In the Pacifier Diesel is a navy Seal who is forced to watch kids after he fails in a mission where he was supposed to protect their father. THIS NEVER COMES UP LATER. The reason that he has to watch the kids is because he got their father killed. This movie is supposed to be a comedy. Way to kick it off.
During the first part of the "film" he comes off as pretty strict and all the kids hate him. He wont let them do anything and yells all the time. It looks like they will never get along... until ninjas attack. Diesel fights off the ninjas and the kids are so grateful that they realize that he was only trying to protect them by being so strict.
Diesel uses Karate to solve most of the problems in the movie. One girl's scout troop is being constantly harassed by a cub scout troop so Diesel teaches them karate so that they can fight the boys off. One kid is constantly harassed by his pushy Vice Principal at school. Diesel beats up the Vice Principal in front of the entire school. Etc... etc... until the entire cast somehow knows karate and defeats evil by kicking it in the balls. (This was a kids film.)