His reasoning is sound; why spend state money on a program that might be declared unconstitutional in a couple of months?

NJ.com:

Gov. Chris Christie vetoed a bill today that would have required the state to form a "health exchange," a marketplace accessible online and by telephone that small employers and uninsured people would use to shop for low-cost coverage.

The veto does not come as a surprise. The health exchange is a key component of the federal health care law, and the Christie administration has delayed implementing aspects of with the Affordable Care Act before the U.S. Supreme Court rules whether the law is constitutional. The court's decision is expected in June.

"While I appreciate the Legislature's attempt to find steady policy footing in these shifting legal sands, I am concerned that a hastily created exchange in New Jersey will impose unnecessary obligations upon the state's citizens,'' according to the governor's veto statement released today.

"I believe the better course of action for New Jersey is to continue to monitor the ever-changing landscape surrounding the implementation of the Affordable Care Act, and to refrain from imposing its mandates upon our citizens until outstanding issues are settled and the required course if action is clear,'' according to the statement.

The governor's decision will disappoint consumer advocates at the AARP, which commissioned a poll that found 58 percent of residents favored the exchange. The lack of health care is a significant issue for AARP because About 200,000 New Jerseyans ages 50 to 64 lack insurance and are too young to qualify for Medicare.

Some studies have shown that the exchanges, even without the federal program, may make insurance premiums cheaper for some families. And the exchanges would also be valuable in insuring those with pre-existing conditions. The state could set up insurance pools that would spread the risk, thus making such insurance more affordable.

But these are theoretical observations and not proven in practice. Christie was right to veto the measure, which would tie the state's hands in creating their own program.