Arizona's state legislature approved ObamaCare's Medicaid expansion in two closely watched votes on Thursday, handing a victory to Republican Gov. Jan Brewer and a defeat to conservative lawmakers.
The policy will take effect next year and extend healthcare coverage to 300,000 low-income patients in Arizona.
"With the landmark votes in the House and Senate, legislators have tackled the issue that is Job One every session — adoption of a responsible state budget — and enacted Arizona's most sweeping healthcare legislation in decades," Brewer said in a statement after the votes.
"It will extend cost-effective care to Arizona's working poor using the very tax dollars our citizens already pay to the federal government."
The Medicaid expansion is a core component of the Affordable Care Act, and many Republican governors have refused to pursue it as a way to thwart the law.
Conservatives also argue that longer Medicaid rolls will sink state budgets, especially as healthcare costs rise.
Brewer's support for the expansion came as a surprise to people familiar with her strong opposition to ObamaCare.
The governor, in office since 2009, has also been a vocal critic of President Obama on immigration issues, leading to a heated confrontation between the two on a Phoenix tarmac in 2012.
In a January speech, she vowed to create "circuit breaks" to protect Arizona's budget from onerous Medicaid bills.
"I won't allow 'ObamaCare' to become a bait and switch," she said to applause from Republicans.
Twenty-three states, mostly led by Democrats, are pursuing the expansion. Twelve are still deciding, and 15 have refused the option outright.