Former Uttar Pradesh Congress leaders Lalitesh Pati Tripathi and Rajesh Pati Tripathi joined the Trinamool Congress on Monday. "In a bid to use one form of extremism to fight another, [Congress] compromised on the valuable principles that Gandhi and Nehru propagated and left behind," Lalitesh Tripathi said. Both the leaders joined TMC in the presence of party supremo Mamata Banerjee.