Jethmalani also hit out at Gadkari for not being active on the issue of Presidential election in which the government is planning to field Finance Minister Pranab Mukherjee.
He cautioned BJP, saying this would lead people to believe that BJP has something to hide and hence has become an "impotent spectator" to the loot of our finances.
"Today, the nation has realised that its poverty and destitution are the result of widespread corruption and large- scale larceny of the national assets by mainly our present rulers. I am convinced and so is the nation by and large that half the present cabinet ought to be in jail," Jethmalani said in the letter dated May 23.
Addressing Gadkari as a colleague in the letter, the Rajya Sabha MP says he presumes the former would be concerned about the "sickness of our party" which registers no response to the even greater sickness of the ruling party.
"Our party leaders should be going round the country and proclaiming the stark truth. Our party workers must be holding demonstrations in every city and hamlet, in fact every nook and corner of the country. The nation wants feverish action," Jethmalani said.
He said that instead the country has got "tongue-tied leaders busy pulling down one another and creating an unmistakeable impression that they are suffering from some inexplicable inertia and paralysis".
