Dirty tricks by government are not unknown. I'd like to see a time line of the arrest, and his actions before and after.
If he was beginning to be critical (or was expected to be so) before the 'arrest', I'd doubt its authenticity.
He is too high profile a critic to be left unmolested.
Had the administration want to embarass him, why wasn't this publicized at the time of the arrest?
And if it was a set-up and the evidence faked, why didn't Ritter fight the charges? It's certainly within his constitutional rights. In fact, if someone was falsely charged, I'd demand that all the evidence came out so people would be able to make an informed decision about his guilt or innocence.