Somnath Chatterjee thought that Speakers post is equivalent to that of President of India. He betrayed his party at a crucial time. He done it beaccause he is certain that his political life is almost over. No more elections to contest as his constituency baccame a Reserved seat. So this was the best decision for him, now he beccame the pet of the rulers and the media. He can dine with PM and Soniaji and be happy.