Congress really knows how to shoot itself in the foot and to stab a loyal Ally in the back.
Take the case of Lalu Prasad Yadav. He has steadfastly stayed in the 'sickular' corner, has been firm in his opposition to BJP and has supported Congress at every turn during the past few decade. And he was a better than decent Railway Minister. But when UPA 2 was formed, he was pushed aside rudely and without even a courteous 'thank you for services rendered' by the Congress. The result? Lalu went alone in the Bihar elections, was beaten, but ensured Congress under the (de)motivating leadership of the Clown Prince was soundly thrashed, which put a black mark in the 'future' Prime Minister in waiting's resume. If only Congress had shown some magnanimity and offered Lalu a couple of Ministries, they would not have been in such a sorry state.
The Left supported Congress with outside support during UPA 1. And they were pretty decent about it. They got all the flak for government non performing, as the Congi friendly media portrayed them as the stumbling block that the genius liberal reformist PM couldn't overcome. They were shown the door for a silly nuclear deal, and if you would have expected Congress to go back to the reform agenda now that the shackles have been broken, you were mistaken. Looking at the (non) performance of post Left UPA, one has to give a compliment to Left for getting something done by the Government, as they are hardly doing anything other than looting the Country. That Congress tied up with TMC to bring down Left in Bengal is the icing on the cake. But looks like Didi is jittery as she is apprehensive Congress is up to their old tricks. She is being very wary.
Congress did the same to Shibu Soren, who, once, bailed it out with a few suitcases.
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But if I were Congress President, I will tie up with my alliance partners for a long period, and ensure the coalition is stable for a while, rather than torpedoing it at every single opportunity.