There is little risk that the candidate will sue you or prevail because the First Amendment provides a great deal of latitude for discourse on matters of public concern.  This presidential candidate should expect all kinds of scrutiny, criticism and debate.  On the other hand, if, without factual support, you identify the special interest groups or name individuals you claim made illicit payments, one or more of them may be inclined to sue you for defamation.  Bottom Line: While under the facts presented here, you’d be on relatively safe ground, tweaking the facts a bit to a situation in which an online contributor is long on specific allegations against identifiable individuals or companies and short on facts and documents to support those accusations and the risk surges.

Depending upon how you got the information and jurisdiction, there may be little to no risk.  In many jurisdictions, you can’t defame the dead.  The convicted serial killer’s reputation is so bad that he or she is likely defamation-proof — has a reputation so tarnished that it can’t be worsened by your report.  Plus, if your reporting is based upon court records or proceedings, you’ve got added protection against defamation risk.  Now, if you name the victim’s friend and inaccurately indicate the two friends shared the addiction problem without basing your reporting on court or government records or reports and without bothering to check the facts, the risk soars.

Little risk because you’re generally safe when providing a fair report of a government proceeding or court case.

Danger Zone.  Report this inaccurately or without substantiation and you could find yourself hiding behind an anonymous and thus flimsy source in the face of an angry plaintiff with lawyers on staff and a big budget for legal fees.

Little risk because Section 230 of the federal Communications Decency Act provides protection to those who provide the platform but aren’t actively generating the content in question.  Basically, you wouldn’t be the publisher of the content that had been created and posted on your blog by another.  You’re responsible for the content you create but, to the extent that you’re the passive recipient and conduit of someone else’s content, you’ve got some strong federal statutory protection against legal risk.

No risk, provided the errant balloter is truly unidentifiable.  On the other hand, if you identify the double voter as a Subaru driver with red hair or as one of 10 members of the library’s reading club, you could find yourself facing a defamation lawsuit.  In the red hair and Subaru example, readers may be able to identify your subject, even if you haven’t spelled out her name in print.  In the reading group example, you may have hurt the reputations of everyone in the group and one or more of them could bring a theoretically valid claim.

No risk.  This is parody, which, by definition is false, but you’re safe nonetheless.  Provided you’re publishing obvious parody rather than something that could be confused with fact, you’re generally protected under the First Amendment. (Of course, this doesn’t give you license to publicly charge your accountant with money laundering and claim it was a joke.)