Updated

A Democratic senator from Nebraska who played a crucial role in getting health care legislation passed in the Senate last month has asked South Carolina's top attorney to "call off the dogs" -- a reference to the state official's threat to challenge the constitutionality of the bill.

In a phone call Thursday, Sen. Ben Nelson, D-Neb., urged South Carolina Attorney General Henry McMaster to reconsider, Politico reported. McMaster is  the head of a group of 13 GOP state attorneys general who are threatening to file a lawsuit against the Senate health care bill.

Nelson asked McMaster to "call off the dogs," according to a copy of the memo sent by McMaster's chief of staff to other GOP state attorneys general detailing the call and obtained by Politico.

The attorneys general are challenging the constitutionality of a Medicaid provision in the bill that they say benefits Nebraska at the expense of other states.

The deal Nelson cut with Senate Democratic leaders to gain his critical vote would exempt Nebraska from having to pay for the coverage of new enrollees into its Medicaid program and leave the tab with the federal government -- a move expected to cost Uncle Sam $100 million over the next 10 years.

But Nelson told McMaster that the deal wasn't his idea and that the same Medicaid exemption would be offered to every state, according to the memo.

McMaster told Nelson that the state attorneys were seeking to remove the Nebraska Medicaid provision from the bill and that "he saw no way that he -- nor any of the state attorneys general " will support extending the provision to every state, the memo said.

Click here to read the full Politico story.