Your question is a lot trickier than you might think at first. A lot of comments seem to imply that any potential employer that opts to pass on your resume base

Your question is a lot trickier than you might think at first. A lot of comments seem to imply that any potential employer that opts to pass on your resume based on you testifying is a company that you wouldn't want to work for. Maybe, but I don't think that's how most HR departments would be considering it. Their goal is to add value to the company with each hire. They could agree with your ethics and even applaud your speaking out, but still pass on you because your past history as a whistleblower (or at least close enough to one for the term to broadly fit) makes them nervous about what you might do over a difference of opinion even if they believe their company to be ethical and law-abiding. Unless you happen to be a major witness in the case and the defense manages to drag you thoroughly through the mud, it's unlikely that your CV will be tarnished enough for it to be automatically rejected as though you marked down a felony conviction on the application. It's not completely analogous, but imagine a hypothetical case where Edward Snowden is applying for a position at Google. Were you to poll Google employees, I'd expect strong support for his actions. Hell, his leaks clearly benefited Google by informing them what the NSA was up to and how they were tapping into their internal traffic. But would that support prevent them from worrying about what might happen if he disagreed about certain activities at Google? Snowden already demonstrated a strength of character strong enough to go against the massed might of the United States government of all entities, and for all of their marketshare, Google's own reach pales in comparison. I don't think it'd automatically disqualify Snowden, but it's something that would probably be considered at least in part. For an employer, it boils down to a simple risk analysis. What's the likelihood that the applicant will find themselves in a similar situation again, and how does that weigh against the value that their work would add to the company? There's really no simple answer here, let alone a guaranteed one. If you're a strong candidate that they'd otherwise want, it'll matter less would be the case if you had little to offer them compared to other candidates.