Chennai, Feb 12 : A day after calling on Tamil Nadu Governor Ch Vidyasagar Rao, BJP leader Subramanian Swamy today said the former has to decide on the issue of government formation by tomorrow else a court case “can be filed charging abatement of horse trading”. “The TN Guv must decide CM issue by tomorrow otherwise a WP under Art 32 of the Constitution can be filed charging abatement of horse trading,” he said in a tweet.