SPRINGFIELD — If a graduated income tax amendment goes through, Senate President John J. Cullerton wants to help the wealthy by eliminating the state’s estate tax.“I feel that it’s irresponsible to eliminate [the estate tax] now, but if this constitutional amendment and the tax rates we pass were to become law, it is something which would be responsible in light of the fact that we are asking wealthier folks to pay more in taxes,” Cullerton said.It’s a plan members of the House …