(TNS) — Whether thousands of Kansans are allowed to enroll in Medicaid may hinge on the people running for governor.

The Republican field now includes three candidates with connections to health care. That's spurring talk that Medicaid expansion could play a significant role in the race.

Lt. Gov. Jeff Colyer, a plastic surgeon, and Ken Selzer, who helps regulates health insurance as state insurance commissioner, entered the race last month. Jim Barnett, a former state senator and physician, began campaigning in June.

Their backgrounds may elevate the prominence of health care issues in the GOP primary, and force a debate over Medicaid: Barnett supports expanding eligibility for the program, while Colyer and Selzer have expressed opposition.

"Where the candidates stand on Medicaid expansion may be one of the key differentiating factors in this primary," said Bob Beatty, a political scientist at Washburn University.

Republican candidate Wink Hartman, a Wichita businessman, has said Kansas doesn't have the money to pay for expansion. Kansas Secretary of State Kris Kobach opposes expansion, and entrepreneur Ed O'Malley, who is running an exploratory campaign, supports it as long as it is budget-neutral to Kansas, cost increases are covered through efficiencies and Kansas backs out if the federal government does.

Expansion is less likely to play a large role in the Democratic primary because support is widespread within the party.

The fate of expansion for Medicaid — the federal program administered by the states that provides health coverage to low-income adults, individuals with disabilities and nursing care to the elderly — is an open question as Congress tries to change federal health care law. So far, the efforts have been unsuccessful, though some Republican lawmakers have vowed to continue trying.

Medicaid expansion is part of the Affordable Care Act passed by Congress in 2010. A 2012 Supreme Court ruling gave states the option of whether to expand, but Kansas has so far opted against expansion.

"The reality is it will be part of the discussion because it is a primary national issue," said Sen. Barbara Bollier, a Mission Hills Republican who supports expansion.

The federal government currently pays for 90 percent of the expansion costs for states that extend Medicaid coverage to people at up to 133 percent of the federal poverty line.

Some 150,000 Kansans could join Medicaid if the program is expanded, supporters say. Critics contend expansion could saddle Kansas with unaffordable costs, especially if the federal government reduces or eliminates its cost share portion.

"I think it will be a big issue. It's a big issue for everybody," Sen. Pat Roberts said when asked if Medicaid expansion would have a role in the race for governor.

The Kansas Legislature approved expansion this spring, but Gov. Sam Brownback vetoed it. Supporters didn't have enough votes to override the veto.

"The fact that lines have already been drawn on the issue would by itself indicate it will be an issue. Obamacare, and parts of Obamacare such as Medicaid expansion, is not popular with GOP primary voters," said Jeff Glendening, director of the Kansas chapter of Americans for Prosperty, which opposes expansion.

David Jordan, director of the pro-expansion Alliance for a Healthy Kansas, said Medicaid will be a major issue in both the gubernatorial campaign and during the next legislative session.

But he pointed to an April poll of 500 likely voters commissioned by the American Cancer Society Cancer Action Network and the American Heart Association, which both support expansion. According to the poll, 66 percent of Republican voters in Kansas support expansion.

"Our hope is that we're able to pass Medicaid expansion during the session, but I think you can see, regardless, it will be a topic discussed during the primary," Jordan said.

How big of a topic may depend on whether candidates use either opposition or support for expansion as a cudgel against other candidates.

Barnett has been vocal in his support. Rep. Dan Hawkins, a Wichita Republican who opposes expansion, said candidates who promote their support for the policy do so at their own peril.

"Quite frankly, in the Republican primary, if you're for Medicaid expansion, you're probably going to be in the minority," Hawkins said.

Hadassah Prosser, who has degenerative disc disease in her lower back that affects how long she can stand and walk, said at a pro-expansion forum in Wichita recently that she prays that Kansans support expansion through their vote.

She has an aide who is funded by Medicaid. Her daughter, who is also disabled, also receives services through Medicaid.

"It's going to affect (the race) highly, because we need a governor who supports the expansion of KanCare and for people who are disabled and the seniors and our youngsters that need the help," Prosser said. "I desperately, desperately need the expansion."

The Eagle's Katherine Burgess contributed to this story.