More importantly, one of the main reason that services like Kelly are used is that Kelly is the employer, not the company that is contracting for services from Kelly, and Kelly didn't fire you -- a company that was contracting with them exercised an option under their contract with Kelly to stop receiving services from Kelly. As a result, Kelly doesn't have any work for you until they get another request that you fit.
Its pretty hard to have "genuine wrongful termination" without actual termination. Especially if the staffing agency quickly finds you other work, even if the other company motivation was "wrongful", you're going to have a hard time establishing compensable harms stemming from it.
If the staffing agency knew of the wrongful reason, and because of it (or because of the other company's decision to end your assignment with knowledge of it) they then declined to assign you other work, you might have a case for wrongful termination case against them (by way of constructive dismissal), but there would seem to be a number of things you'd have to prove there that you wouldn't in a direct employment wrongful termination case.
'Its pretty hard to have "genuine wrongful termination" without actual termination.'
IANAL, but my understanding is that judges pretty quickly look past what things are labelled. If the temp was able to quickly roll into another gig (or the temp agency otherwise kept paying them), that's one thing. But I'd still be very surprised if legal cleared "We don't have need for your services any longer because you're black. We're contacting your temp agency for a white replacement."
