The agency has produced two 30-second spots which will trail Sunday's Channel 4 News debate hosted by Jon Snow on whether or not there should be a war with Saddam Hussein.
The trailers pose the awkward moral questions raised by the issue and ask: "Whose side are you on?"
M&C Saatchi won the assignment, commissioned by Tim Gardam, Channel 4's director of programmes, after five agencies and creative consultants were asked to submit concepts at very short notice. Channel 4 cited the agency's experience in political advertising as the reason for is choice.
The senior agency creatives Tiger Savage and Mark Goodwin produced the films. One warns of the possibility that the Iraqi dictator might be prepared to use anthrax as a weapon. The other asks if Britain should be supportive of US action.
"The idea is to indicate the surprising views some people might take about a Middle East war," a Channel 4 spokesman said.
The agency had to work fast on the project, producing scripts over a weekend after an informal briefing on the previous Friday evening. "We were happy to work fast because we were passionate about the project," Judy Mitcham, the agency's new-business director, said.
The films were produced by Channel 4 Creative Services and directed by Siri Bunford.