COLUMBIA — The South Carolina gubernatorial election won’t arrive for another 18 months, but the ad wars began Wednesday.

A new online and TV advertisement attacking likely Democratic gubernatorial nominee state Sen. Vincent Sheheen’s support for Medicaid expansion began airing in markets across South Carolina.

Meanwhile, the Democratic Governors Association released an online clip slamming Gov. Nikki Haley’s “gallery of corruption.”

The spots represent some of the first shots in the expected 2014 rematch between Sheheen and Haley.

A political group run by supporters of Haley, The Movement Fund, is responsible for the 30-second anti-Sheheen ad.

The group has spent about $300,000 so far to air the ad on both network and cable television in the Greenville-Spartanburg, Florence-Myrtle Beach and Charleston markets, said consultant Tim Pearson, who advises the group and Haley.

The ad is set to run for 10 days.

The spot claims Sheheen, a Camden Democrat, wants South Carolina to be the only state in the South to accept “Obamacare,” formally known as the Patient Protection and Affordable Care Act. The spot goes on to say Obamacare would raise health care costs, squeeze out private coverage and cripple state budgets. “Tell your senator to reject the Sheheen-Obamacare disaster,” the ad concludes.

In March, Sheheen said he supports a temporary expansion of Medicaid — the federal and state program that helps with health care for the needy, old or disabled — for the period when the federal government would fully cover that cost.

After three years, the state would have to cover a portion of the cost of the expansion, rising to a maximum of 10 percent in 2020. Accepting the expansion would provide health coverage to hundreds of thousands low-income South Carolinians.

Sheheen has said the state should revisit the issue after the first three years.

Haley’s administration has long been opposed to an expansion, and the GOP-controlled General Assembly has so far rejected Democrats’ attempts to accept the expansion.

Sheheen’s campaign called the pro-Haley group’s ad “patently false.”

“It’s a move that shows she’s not only vulnerable, but also that she and her closest advisors know it,” the Sheheen campaign said in an email to supporters.

State Sen. Brad Hutto, D-Orangeburg, came to Sheheen’s aid, saying in a statement that accepting the Medicaid expansion would bring South Carolinians’ tax dollars home and create tens of thousands of jobs.

Other Southern leaders support an expansion of Medicaid in their states.

Florida’s Republican Gov. Rick Scott has said he supports expansion, but the Florida House has rejected it.

Arkansas Democratic Gov. Mike Beebe and the state’s GOP-controlled legislature have reached a compromise that would have the state accept the federal cash meant for Medicaid expansion and instead use it to buy private insurance for low-income residents.

Other states are eyeing the approach, which must win federal approval. The DGA clip criticizes Haley for, among other things, coming under investigation by the House Ethics Committee for alleged illegal lobbying while a House member from Lexington. Haley successfully defended herself against the allegations last year, when the committee twice cleared her. Pearson dismissed the spot, saying Haley championed a wide-ranging ethics reform bill that passed the House this week. Washington Democrats concerned about ethics in South Carolina should focus on making sure Sheheen and his Democratic colleagues in the Senate pass a strong ethics reform measure this year, Pearson said in a statement.

Sheheen has announced a bid for governor, setting up a rematch of the 2010 race in which Haley bested him by about 4.5 percentage points.

Haley has not officially announced that she will seek re-election, but is expected to do so this summer after the conclusion of the legislative session.

Reach Stephen Largen at slargen@postandcourier.com and follow him on Twitter @stephenlargen.