Even Carl C. Icahn, the activist investor who has long pushed companies to consider cost-saving maneuvers, has now begun to worry about the harmful effect of corporate inversions. He has begun waging a campaign in Washington to reform the corporate tax system.

“How will representatives and senators, with an election year approaching, explain to their constituents why they are out of work because their employers left the country, when it could so easily have been avoided?” he wrote on the Op-Ed page of The New York Times last month.

And consider this: Johnson Controls, currently based in Milwaukee, has aggressively sought — and received — a series of tax breaks and other deductions to do business in the United States. Between 1992 and 2009, the company received at least $149 million in tax breaks from Michigan alone. Last year, Johnson Controls had to pay a $3.75 million penalty to Michigan after it received a $75 million tax break in exchange for creating 400 jobs at its Holland lithium ion plant. The company fell short on the job creation, so it was forced to compensate the state and give up its tax-exempt status at the plant. In 2011, Johnson received a tax break from Kentucky in exchange for expanding its operations there.