#RajivGandhi Govt was responsible for bringing in a ridiculous law which still exists: Anti-Defection.
While it's a good law to prevent people from jumping parties, it's also a horrible law which binds elected representatives to the whims & fancies of party leaders.
For a simple (and fun) breakdown, watch this:
Why, you ask? Because all of them benefit. It concentrates power in hands of the top leadership. Individual MPs are just numbers, not representatives.