If he actually quit verbally at this meeting, it makes the plot more legitimate and explosive...he quit in reaction to a domestic terrorist plot. What he didn't do is report this.
Not unless he was an FBI informant/mole. If he was and is forced to admit that, he will suffer just as much as he would if it turned out that he didn't report it. The only difference is that he will be hurt with his own voter base rather than with swing voters.