The Maine Senate campaign will be, to some extent, a test of the power of source credibility.
Almost all the ads run by Republicans for the U.S. Senate seat now held by Olympia Snowe have been negative. Besides one positive, largely biographical ad by Republican nominee Charlie Summers, the rest attack Angus King (and sometimes Cynthia Dill) or tout Dill while criticizing King.
A new ad falls into the same pattern. It’s an attack on King and Dill.
So, how does source credibility come in? And, what is source credibility, anyway?
Source credibility means that people are more or less persuaded by a message depending on what they think of who is delivering the message.
If one trusts an individual or organization, one will find the message more credible. This is why Barack Obama’s campaign is helped by having Bill Clinton make arguments on his behalf. Over two-thirds of Americans see Clinton favorably and so he was the speaker people most wanted to hear from the two national party conventions.
Likewise, if a source is not trusted and is seen negatively, then messages from that source are not given a lot of weight.
In the most recent ad attack on Angus King, who is the source of criticism?
At one point, the ad says, “Congress had to investigate,” while images mention the “Feds” and the “House Oversight Committee.”
What kind of credibility do these sources have?
Not much in the general public.
The House is controlled by Republicans, and Republicans have lower levels of approval than Democrats.
According to the most recent NBC/Wall St. Journal poll, 42% see the Democratic party favorably and 40% see it negatively, for a +2 net in favorability ratings.
In contrast, 36% see the Republican party positively and 45% see it negatively, for a -9 net in favorabilities.
So the sources used in attacking Angus King are not well-liked and not particularly credible overall. Congress has low approval among all political groups, including Republicans.
In fact, King’s core message for electing him relies on this aspect of public opinion — a widely-held distaste toward Congress and how Congress is doing its job.
One part of that job is investigating such things as wind power. It’s not likely that an institution that’s seen as overly partisan is widely trusted as a fair investigator.
Given this, a King critique based on what Congress said runs up against the institution’s limited source credibility. In other words, many people won’t see the institution as a credible source of information regarding this independent candidate.