Iowa Attorney General Tom Miller has joined his counterparts from eight other states to file a brief in support of the federal government in a Michigan case that says the healthcare reform act is unconstitutional. The lawsuit says the federal government can’t force Americans to buy health insurance.

Miller, a Democrat, says he believes the act is constitutional under the commerce clause. Miller says those that don’t get insurance coverage cost billions of dollars each year that everyone else picks up each year, and he says those billions of dollars have a major impact on interstate commerce.

Miller says requiring insurance is an important part of making the law work.

Iowa Governor Terry Branstad, a Republican, recently announced he was signing onto the Florida effort to overturn the law. Miller says he and Branstad talked about their different positions and work out a way to do that. Miller says it was a somewhat unusual situation where he says the governor had “a lot at stake, and had a pretty strong position contrary to mine, so out of respect to him and his office…I agreed that he would enter not as the State of Iowa into the lawsuit in Florida, but as the governor of Iowa.”

Miller says he is not sure how many other states have a similar situation where the attorney general has a different position than the governor — but says there are others. All of the attorney’s general that are offering their support of the Michigan case are Democrats, but Miller and the others say they are doing so to protect the Constitution and not because of politics.

“I think the law is strongly on the side of constitutionality, and I am hopeful that the circuits will decide in that way,” Miller says. The attorney’s general in California, Oregon, Connecticut, New York,

Maryland, Delaware, Hawaii  and Vermont are also joining in the friend-of-the-court brief. The Michigan case is one of several in the courts over health care reform.

The group of state lawyers say they will look at other legal challenges to the law and may also join them in support of the federal government’s case.

Updated at 3:55 p.m. to add additional states.