India, May 31 -- Karnataka's political history offers a recurring warning for parties attempting to replace powerful regional leaders before the end of a term: the administrative transition may be immediate, but the electoral consequences often unfold slowly.

That history now hangs over the Congress as Siddaramaiah exits the chief minister's office and D. K. Shivakumar prepares to take charge under a long-discussed power-sharing arrangement.

Within the Congress, the transition is being viewed through the prism of two earlier political moments that altered Karnataka's electoral landscape far beyond the change of leadership itself. The first was the removal of Veerendra Patil in 1990. The second was B. S. Yediyurappa's resignation as chie...