Gov. Pat Quinn says proposed changes haven't weakened his opposition to legislation that would raise electricity rates and modernize the Illinois power grid.
Quinn says the changes simply "paper over" problems that make the bill bad for Illinois consumers.
At a news conference Tuesday, Quinn said he will work with the attorney general, AARP and other groups to block the legislation.
The "Smart Grid" bill was approved in the spring, but Quinn vetoed it. Now supporters are trying to override his veto by introducing a second bill that would lower power companies' profits, impose tougher performance standards and put more money into infrastructure improvements.
Critics say it would still weaken regulators who oversee power companies.