From the Huffington Post :
By rewriting the rules that govern which strings the federal government can attach to its spending on the state level, Chief Justice John Roberts may have inadvertently prevented a future Tea Party-dominated Congress from executing one of its top priorities, defunding Planned Parenthood.
At the same time, it raises the question of whether the federal government can withhold Medicaid money if a state decides on its own to defund Planned Parenthood. Before Roberts' ruling, no legal scholar would have questioned whether the federal government had the authority to spend its own money or tie any strings it deemed appropriate to it. But after the ruling, it's an open question that will likely be decided in court, legal experts told The Huffington Post.
"I perceive NFIB v. Sebelius as throwing the courthouse doors open to coercion claims," said Nicole Huberfeld, a University of Kentucky law professor. "Because the holding is so dependent on the somewhat unusual facts of Medicaid, and because the court set forth no theory of coercion, I think we will see a lot of challenges in an effort to discover the contours of the coercion doctrine."
The issue raised by Roberts' opinion is whether the federal government can coerce a state into using its federal grant money in a particular way by threatening to withhold that money. For instance, if Congress voted to defund Planned Parenthood through the Title X federal family planning program, but New York wanted to continue sending its federal Title X dollars to Planned Parenthood clinics in the state, could the government withhold all Title X money from New York?