The Treasury Department has not responded to a subpoena from the House Oversight and Government Reform Committee Chairman Issa (R-CA) concerning Internal Revenue Service (IRS) documents related to an IRS rule implementing subsidies under the federal health insurance exchange. The Treasury Department, citing executive branch "confidentiality interests," declined to send the requested documents. In a letter last week the Treasury Department said it is unable to reveal details on how it decided federal-run exchanges can provide subsidies in the same fashion as state-based exchanges. The letter also noted that the rule is currently being challenged in federal court by Oklahoma's attorney general, and the department said any questions about the rule should be settled by the courts. "We strongly disagree with these claims, and we intend to defend the lawsuit vigorously."