Senator Chuck Grassley authored the amendment that originally forced congressional staff to go on the Obamacare exchanges — unlike other federal employees who get to keep their current health-care plans. So it was a bit shocking when Roll Call reported he had chosen to exempt his committee aides from the requirement under a special loophole crafted by Senate majority leader Harry Reid.

I caught up with Grassley as he left the Capitol just now. He tells me the decision was based on advice he received from the secretary of the Senate on how to proceed.

“I went to the secretary of the Senate and got advice on which the secretary of the Senate considered the law to read. And I’ve done exactly what the law says,” the Iowa Republican says.

However, a close inspection of the regulation issued by the Office of Personnel Management says the decision is ultimately Grassley’s, whatever the secretary of the Senate counseled. In fact, the regulation explicitly states that the OPM “will not review or overturn” the decisions by each congressional office to determine whether the requirement applies to them.

Grassley’s explanation is also belied by the decision of every Republican leadership office, with the exception of Vice Conference chairman Roy Blunt’s leadership staff, to put their aides on the exchanges. Most Republican committee chairmen and ranking members are following suit, with some exceptions.

I pressed Grassley on these facts but he insists he was just “following the law.”