Annamalai is right, the fight is between BJP and DMK and not AIADMK. Let AIADMK if it desires, fight DMK. Fight of BJP in Tamil Nadu should focus on corruption where both the Drawidians parties would go defunct.
EPS might have been under the calculation that by moving away from NDA, he can attract congress and other fringe players into his fold but that looks farfetched as on date mainly due to the lack of trust and ability of EPS and his party to win any seats in coming election.
AIADMK has been dying, but thanks to the support of Modiji, the death of the party got delayed. But now EPS has decided to bury the party alive by deciding to snap ties with BJP in the state.