Does the Nebraska Compromise secured by Sen. Nelson make Senate health care reform bill unconstitutional?

Sen. Graham (R-SC) and Sen. DeMint (R-SC) have requested State Attorney General Henry McMaster to look into "concerns about the constitutionality of this Nebraska compromise as it results in special treatment for only one state in the nation at the expense of the other 49" (http://www.msnbc.msn.com/id/34551523/ns/politics-health_care_reform/). The Nebraska Compromise is in reference to the deal that Sen. Nelson (D-Neb.) was given to exempt citizens in Nebraska from the cost of the $45M, annually, expansion of Medicaid program in exchange for his vote on the Senate health care debate. Other states working with Attorney General McMaster include Alabama, Colorado, Michigan, North Dakota, Texas and Washington. Just a few seconds ago on MSNBC McMaster announced two more states have joined the effort as well.

Texas Attorney General Greg Abbott defended his decision to join the discussion by saying, "The Nebraska Compromise, which permanently exempts Nebraska form paying Medicaid costs that Texas and all other 49 states must pay, may violate the United States Constitution, as well as other provisions of federal law. In light of this unprecedented and highly questionable backroom deal, Texas will join South Carolina and other states in an effort to thoroughly review the constitutionality and legality of the Nebraska Compromise" (http://www.fortbendnow.com/2009/12/23/42918). While "backroom" deals are nothing new to the political but the difference between traditional "backroom" deals and the Nebraska Compromise is that traditionally the deals result in a onetime influx of money for a pet project. That is the core of the argument being made with the Nebraska Compromise is that it unfairly benefits one segment of the population. Other states were involved in getting special funding as well for Medicaid expenses which include Louisiana, Massachusetts and Vermont.

Obliviously this will play out but does the deal that Sen. Nelson secured violate the Constitution? Is it fair to the rest of America to pay for all Medicaid costs of Nebraska going forward?