David Strathairn nearly won an Oscar for his portrayal of TV newsman Edward R. Murrow in 2005’s “Good Night, and Good Luck.”

As a campaign spokesman, however, he’s not nearly as effective as the mother of a dead soldier, according to a study by Wilson Research Strategies.

Neither Rep. John Sweeney (R-N.Y.) nor Democratic challenger Kirsten Gillibrand are the stars of their ads. But while Gillibrand’s ad has movie-star appeal and nostalgia — it shows Strathairn resurrecting his role as Murrow and comparing Sweeney to Sen. Joseph McCarthy (R-Wis.) — Sweeney’s ad packs the kind of broad appeal he prides himself on and will need if he’s to win a fifth term this November.

Even Democrats rated Sweeney’s ad better, preferring it 45 percent to 25 percent for Gillibrand, with 20 percent undecided and 9 percent saying neither was effective.

Independents and Republicans also preferred Sweeney’s ad over Gillibrand’s, 56-25 and 49-28, respectively.

“It shows that Sweeney’s going out of his way to appeal across party lines,” said Chris Wilson, CEO of Wilson Research Strategies. “I think his appeal has always been across party lines, and its clear that is the case” with this ad.

Sweeney’s ad features a mother who says she met Sweeney the day she buried her son, who died in Iraq. She praises Sweeney for keeping a promise to work to increase body armor for soldiers in Iraq and explains that, while she’s against the war, she’s for the troops and for Sweeney.

The ad actually scored best among Democrats, who gave it a 6.9 on a scale of 1 to 10 for the strength of its message. Independents rated it about the same as Republicans, who gave it a 6.3 for its message strength and a 6.4 for credibility.

The ad also scored well with members of the news media, who tend to rate ads lower than other groups studied. They gave it a 7.1 for both strength of message and credibility.

Gillibrand’s ad shows Strathairn in an environment similar to that of “Good Night and Good Luck” and Murrow’s newscasts. Like the movie and TV in Murrow’s age, it is in black and white.

Strathairn accuses Sweeney of attacking Gillibrand and her family, and casts him as a bully who needs to be stood up to, much like McCarthy in Murrow’s era. The well-worn phrase “Have you no decency?” is used throughout.

The ad scores a 4.4 for its effectiveness, well below the 5.6 average. Independents scored the ad even worse than Republicans.

Working with The Hill for its Air War feature, Wilson Research Strategies e-mails campaign or issue ads to survey participants who view the ads and rate their effectiveness on several criteria.