Como nestes exemplos:

Politicians treat voters like idiots | The Guardian | Guardian ...
Across the whole electoral dossier, calculated obscurities abound. The people are held not to be worth entrusting with jagged facts. ...
www.guardian.co.uk/guardianpolitics/story/0,,496323,00.html

Reference Search - AOL Research & Learn
Macuacua stressed that the electoral dossier. Premium Content: AOL Family Library Date: 2005-07-06 | Word Count: 790 | Grade Level: 6 - 12 More Like This ...
http://reference.aol.com/search?id=135002205&suggest=true&qu...

Romania Lg - El - Cn - Cd Introduction About the Project The ...
For the Presidency of Romania the report and the electoral dossier are forwarded to the Supreme Court of Justice. In cases where the court ascertains that ...
http://www2.essex.ac.uk/elect/database/legislationAll.asp?co...

This fits with the rest of the sentence, which indicates clearly that it was for use in the election campaign.

The term "electoral dossier" does not work because the dossier was not related to the election itself, to the right to vote, to election rules and regulations. Even though it is a "correct" translation it does not "mean" anything to the reader.

I don't know the context of the entire document but it appears to be intended to inform the reader of political developments in Brazil.

From long experience in translating this sort of material (throughout the Collor administration and even before then) I have lost my fear of straying from the literal in order to accomplish the purpose of the report. Now, if it were a traducao juramentada in Brazil, we'd see "electoral dossier" - we would have to, and puzzled readers.

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Note added at 3 days13 hrs (2007-03-19 14:25:42 GMT)
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a dossier always contains potentially incriminating information and doesn't need any adjectives