House Committee on Oversight and Government Reform chairman Darrell Issa (R‑CA) writes in the Washington Examiner: 

To combat the sticker shock of Obamacare’s numerous requirements on health insurance premiums, the law creates expensive subsidies, which take the form of tax credits, for individuals who purchase a government-approved insurance plan. In order to avoid the appearance of a federal takeover of health care, the law ties the availability of these premium tax credits to an “Exchange established by the State.” Importantly, the way the law was written, if tax credits are not available within a state, then the expensive employer mandate tax does not apply to companies within that state.

With so many states refusing to play the role the law’s drafters envisioned, the Obama administration has embarked on a legally dubious effort to bypass the plain language of the law. Obama’s IRS has issued a rule that delivers the expensive subsidies through federally run exchanges as well. If it stands, this extralegal rule will undermine the decision-making role offered to states by Obamacare, and cause hundreds of billions of dollars of taxes and spending not authorized by the president’s health care law…

The language that limits tax credits to state-established exchanges should not now shock Obamacare’s supporters. Early in 2009, legal scholar Timothy Jost, one of Obamacare’s leading proponents, explicitly suggested linking the tax credits to state-established exchanges as a way to encourage states to set up the exchanges.

The Obama administration may be surprised and disappointed that many states have not found the refundable tax credit to be a sufficient incentive to set up their own exchanges, exposing their citizens to the other taxes and penalties associated with the law. But this does not justify the administration’s effort to ignore the plain language of the law that Obama championed and signed.

For more on this issue, see Jonathan Adler’s and my Health Matrix article, “Taxation Without Representation: The Illegal IRS Rule to Expand Tax Credits Under the PPACA.”