What this movie gets right is the dry, cynical, slightly gallows-ish humor of people who spend their lives on constant alert, knowing that 999 out of a thousand of the “suspicious” activities they check out will be nothing. They are the guys in the corner of the picture in the paper during the President’s speech. When everyone is looking at him, they are looking at them, deciding whether the man over there is reaching for a cell phone or something more dangerous. For years at a time, they watch to make sure perameters are secure and routes are clear. They are always alert and always ready to die to save the President and his family. The script may be thin, but the performers don’t seem to notice, plowing ahead with the same dogged, somewhat humorless determination real-life agents bring to the job.

Pete Garrison (Michael Douglas) took a bullet when someone tried to kill President Reagan. He’s still on the job, not enough of a rule-follower to be promoted to a management position, but trusted enough to be assigned to guard the President (David Rasche) and the First Lady (Kim Basinger).

Garrison gets evidence from an informant that there may be a traitor within the Secret Service. To make the investigation even more difficult, Garrison is having an affair with the First Lady and his former best friend David Breckendridge (Kiefer Sutherland), the chief investigator now despises him, believing Garrison caused the end of his marriage by having an affair with his wife. Can Garrison protect the First Lady and his informant while finding the mole before he can put the President at risk?

It’s a pretty solid thriller, not worth rushing out to see but worth a matinee or video rental. The transfer from book to screen is uneven. The script does not always show instead of telling — or assuming — what we need to know, especially when it comes to the relationship between Garrison and the First Lady (or between the First Lady and the President), Garrison and Breckendridge, and Breckendrige and rookie Jill Marin (“Desperate Housewives’” Eva Longoria). The characters are underwritten but the stars’ natural charisma holds our attention and keeps us on their side, the action scenes are crisply filmed, and the location shots provide an authentic feel.

Parents should know that this film has a great deal of peril and violence, with a lot of shooting. Characters are wounded and killed. There is blood, but the injuries are less graphic than some other PG-13′s. It includes a non-explicit sexual situation and references to adultery. Characters drink alcohol and use some strong language.

Families who see this movie should talk about the Secret Service and how its training and duties differ from other law enforcement agencies. Did Garrison violate his duty or his oath?

Families who enjoy this movie will also enjoy Clint Eastwood’s portrayal of a Secret Service agent in In the Line of Fire. They will also enjoy the superb miniseries Tinker, Tailor, Soldier, Spy, about a mole within Great Britain’s spy agency, based on the real-life case of traitors Philby, Burgess, and McLean.