Conn. Gen. Stat. § 27-187: Pleading by accused.

If an accused arraigned before a court-martial makes an irregular pleading, or after a plea of guilty sets up matter inconsistent with the plea, or if it appears that he has entered the plea of guilty improvidently or through lack of understanding of its meaning and effect, or if he fails or refuses to plead, a plea of not guilty shall be entered in the record, and the court shall proceed as though he had pleaded not guilty.