Originally printed in The Wall Street Journal, January 6th, 2014

On Monday, Jan. 6, I am filing suit in the U.S. District Court for the Eastern District of Wisconsin to make Congress live by the letter of the health-care law it imposed on the rest of America. By arranging for me and other members of Congress and their staffs to receive benefits intentionally ruled out by the Patient Protection and Affordable Care Act, the administration has exceeded its legal authority.

The president and his congressional supporters have also broken their promise to the American people that ObamaCare was going to be so good that they would participate in it just like everyone else. In truth, many members of Congress feel entitled to an exemption from the harsh realities of the law they helped jam down Americans' throats in 2010. Unlike millions of their countrymen who have lost coverage and must now purchase insurance through an exchange, members and their staffs will receive an employer contribution to help pay for their new plans.

It is clear that this special treatment, via a ruling by the president's Office of Personnel Management, was deliberately excluded in the law. During the drafting, debate and passage of ObamaCare, the issue of how the law should affect members of Congress and their staffs was repeatedly addressed. Even a cursory reading of the legislative history clearly shows the intent of Congress was to ensure that members and staff would no longer be eligible for their current coverage under the Federal Employee Health Benefit Plan.

The law states that as of Jan. 1, 2014, the only health-insurance plans that members of Congress and their staffs can be offered by the federal government are plans "created under" ObamaCare or "offered through an Exchange" established under ObamaCare.

Furthermore, allowing the federal government to make an employer contribution to help pay for insurance coverage was explicitly considered, debated and rejected. In doing so, Congress established that the only subsidy available to them would be the same income-based subsidy available to every other eligible American accessing insurance through an exchange. This was the confidence-building covenant supporters of the law made to reassure skeptics that ObamaCare would live up to its billing. They wanted to appear eager to avail themselves of the law's benefits and be more than willing to subject themselves to the exact same rules, regulations and requirements as their constituents.

Eager, that is, until they began to understand what they had actually done to themselves. For instance, by agreeing to go through an exchange they cut themselves off from the option of paying for health care with pretax dollars, the way many Americans will continue to do through employer-supplied plans. That's when they went running to President Obama for relief. The president supplied it via the Office of Personnel Management (OPM), which issued a convoluted ruling in October 2013 that ignores the clear intent and language of the law. After groping for a pretext, OPM essentially declared the federal government a small employer—magically qualifying members of Congress for coverage through a Small Business Health Options Program, exchanges where employers can buy insurance for their employees.

Neat trick, huh? Except that in issuing the ruling, OPM exceeded its statutory jurisdiction and legal authority. In directing OPM to do so, President Obama once again chose political expediency instead of faithfully executing the law—even one of his own making. If the president wants to change the law, he needs to come to Congress to have them change it with legislation, not by presidential fiat or decree.

The legal basis for our lawsuit (which I will file with a staff member, Brooke Ericson, as the other plaintiff) includes the fact that the OPM ruling forces me, as a member of Congress, to engage in activity that I believe violates the law. It also potentially alienates members of Congress from their constituents, since those constituents are witnessing members of Congress blatantly giving themselves and their staff special treatment.

Republicans have tried to overturn this special treatment with legislation that was passed by the House on Sept. 29, but blocked in the Senate. Amendments have also been offered to Senate bills, but Majority Leader Harry Reid refuses to allow a vote on any of them.

I believe that I have not only legal standing but an obligation to go to court to overturn this unlawful executive overreach, end the injustice, and provide a long overdue check on an executive that recognizes fewer and fewer constitutional restraints.

Mr. Johnson is a Republican senator from Wisconsin.

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