U.S. Sen. Ron Johnson, R-Wis., explains for Wall Street Journal readers why he’s filing suit over the Obamacare exemptions that benefit his fellow members of Congress.

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.

Rewriting a federal law unilaterally? Say it ain’t so.