It’s hard to be shocked when you spend most of your time hanging out in a skimpy nightie talking to dead people. But on tonight’s season finale of “Ghost Whisperer” (7 p.m., CBS), Melinda chats with a ghostly prophet who foretells impending catastrophe. Meanwhile, Melinda appears to be plagued by nightmares, all of them concerning the death of someone near and dear.

¢ “Close to Home” (8 p.m., CBS) also wraps up its run of original shows for the year. In tonight’s drama, a drug arrest blows the cover on a cabal of corrupt cops.

Both “Ghost” and “Close” regularly top the ratings for their night. But winning Friday nights is not what it used to be. In fact, the networks have abandoned the evening to the animals, allowing cable shows like “The Dog Whisperer” and “Meerkat Manor” to get the most critical buzz.

¢ The season finale of “Law & Order” (9 p.m., NBC) won’t air until next week. And there’s a good chance that it could mark a historic event. A TV drama powerhouse since 1990, “Law & Order” and its companion series “Criminal Intent” are in danger of cancellation. “Special Victims Unit” continues to thrive.

The reasons for the decline of “Law & Order” are numerous. “Law” never really recovered from the death of key cast member Jerry Orbach in 2004. The producers seemed to take their eyes off the ball as they expanded the “Law” franchise.

But the real reason for the show’s decline was the shift from “torn from the headlines” true-crime stories to “plagiarized from the tabloids” tales about sleazy media figures. Unfortunately, shows about thinly veiled Kevin Federline types succeeded only in dumbing the show down and alienating its faithful fans.

As of this writing, the decision to swing the ax or save “Law” has yet to be made. But tonight’s episode, about the murder of two homeless men with shared stories about service in Iraq, could mark the second-to-last original “Law” ever. Of course, we have decades of repeats to enjoy.

¢ Hey kids, just in case you missed this, the Media Relations Department at Indiana University did a study on “The Factor with Bill O’Reilly” (7 p.m., Fox News). Academics studied 115 episodes using techniques developed by the Institute for Propaganda Analysis. When they broke down O’Reilly’s rhetoric, they found that he engaged in name calling at a fast and furious rate.

Nobody has ever accused O’Reilly of being lazy. But according to the study, O’Reilly calls somebody a name every 6.8 seconds during his opening editorials. That’s nearly nine insults a minute! “It’s obvious that he’s very big into calling people names,” says assistant professor Mike Conway.

To read the Indiana report and find links to accompanying charts and graphs, go to http://newsinfo.iu.edu/news/page/normal/5535.html.

Tonight’s other highlights

¢ Scheduled on a two-hour “Dateline” (7 p.m., NBC): The brother of a murdered man makes a film with the intent to catch the killer. Instead, police focus on the filmmaker as a possible suspect.

¢ A two-hour “20/20” (9 p.m., ABC): examining the power of faith.