Georgia Governor Nathan DealGov. Nathan Deal has just one week to determine whether Georgia will establish an insurance exchange and enroll in an optional federal program that would swell the state’s Medicaid roster by more than 600,000 new patients.

The health care reform law passed in 2010 required states to broaden eligibility guidelines for Medicaid enrollment lest they faced stiff federal funding penalties. But the U.S. Supreme Court recently ruled that Congress lacked the authority to withhold funding from those states that rejected the expansion effort, effectively neutering the provision.

The decision triggered a chain reaction among Republican governors vowing to not participate, though Deal remained mum for some two months before telling reporters in late August he didn’t have “any intention of expanding Medicaid.”

Deal reaffirmed that position again this week, arguing the associated costs of the expansion–it’s estimated the program would mean a $4 billion tax burden over the next decade for Georgians–would be too great for the already cash-strapped state to absorb.

But the governor has been less clear on whether or not he would establish an online health care marketplace. If Deal refuses to honor the provision, which went untouched by the court in its recent decision, the federal government is required to create the exchange.

Deal told reporters this week he has made a decision, but said he would not publicly disclose it until first notifying federal health officials.

The deadline for both decisions is November 16.

– James Richardson