We had a case in 2002 which has some similarities. A documentary was filmed with hidden cameras as an unknown journalist pretended to be an openly racist voter asking running politicians for their views on the bloody immigrants.
It was released in the lead up to the 2002 election and dented the numbers significantly for Moderaterna (the big right wing party). I think they lost mainly to other parties in the right bloc, so overall election result (Soc.Dems. ruled on) was not much affected.
They filmmakers found politicians from many parties willing to in private damn the immigrants. The reason Moderaterna as hit the worst was in part that the show focused more on them, but also that their aftermath differed. All affected parties condemned (in various trong wording) the politicians in question and in all parties the condemned withdrew their candidacys. Except on guy in Moderaterna who had come off really bad in the program (going off in a clearly racist rant, and then when shown the secretly taped film commented: "eh, well, eh... Thats not me!"), who was a local and popular bigwig who were not going to give up his position. Thus on day 2 of the scandal all parties had manage to withdraw from the spotlight except Moderaterna.
The politicians in question were caught lying (finding somewhere they professed their ardent anti-racism would be an easy task) and resigned. The question left hanging was how many was lying in public and how many simply lied when faced with a voter whos vote appeared up for grabs if they expressed a bit of racism...