Eight years after Obamacare became the law of the land and set the stage for the Republican takeover of the House of Representatives, the issue of health care could come back to complicate GOP hopes of holding that majority in this year's midterms.

For starters, Democrats see the issue as the top concern among voters and a turnout driver for their base in congressional races, more so than the drama du jour emanating from the White House. Additionally, Republicans could find themselves squeezed from multiple sides on the issue, from base voters demoralized over the party's failure to repeal and replace the law to anticipated premium hikes this fall, to members in swing districts where their House vote to undo the Affordable Care Act could be a liability.

"The failure to repeal Obamacare remains a big demotivating concern," said Lanhee Chen, a fellow at the Hoover Institution and policy adviser to GOP presidential campaigns. While the party could play up the repeal of the individual mandate as part of the new tax law, that also carries "the headline risk of 'Premium hike in October,'" Chen said, exacerbating the challenge for Republicans.

Campaign promises to completely repeal the law highly motivated Republican voters in the past, and the failure to deliver "was a deep disappointment to so many activists across the country, who had worked in multiple elections," said Tim Phillips, president of Americans for Prosperity, an advocacy group founded by the Koch brothers. "The tax cuts and tax reform [have] helped alleviate a chunk of that frustration, for sure, as that's a once-in-a-generation accomplishment that impacts almost every American."

Still, the survival of the health care law combined with last week’s passage of a $1.3 trillion government funding bill that defied GOP orthodoxy on federal spending "is a problem for them, there's no question about that," said Phillips. "It could dampen enthusiasm."

Many Republican operatives at this point appear less concerned about turnout, as they have met target goals in the special and off-year elections, and are more concerned about Democratic over-performance in that regard come November. And while reaction to President Trump is fueling enthusiasm among the Democratic base, "campaigns are largely focusing on the economic issues, policy and topics of the day that affect people," said Charlie Kelly, executive director of the Democratic group House Majority PAC. Health care "will continue to be a major part of communications this cycle. ... It's digestible and it's easy to understand for voters."

A Gallup poll released this week found that Americans worry more about health care than any other issue surveyed, with 55 percent saying the availability and affordability of health care matters "a great deal." A Public Policy Polling exit survey of voters in Pennsylvania's special congressional election earlier this month found that the issue was the top concern for 52 percent of voters. The survey from the Democratic polling group also found that more than half of voters in the district disapprove of the Republican repeal efforts.

“There's a reason for Republicans to be concerned. Every poll shows health care is a top issue, that health care costs are a real concern for people,” said Democratic strategist Jesse Ferguson, arguing that Republicans will bear the brunt of criticism from expected premium increases as well as reaction to their repeal efforts that would have curbed coverage for pre-existing conditions. “It's a bit of a perfect storm. They worked to break it and now they own it. Pottery Barn rules apply.”

House Minority Leader Nancy Pelosi encouraged her colleagues to focus on health care during the Easter recess in their home districts, urging them to emphasize rising costs as well as some Republican proposals to offset debt increases stemming from the tax law by reforming entitlement programs such as Medicare.

Republicans argue that Obamacare premiums were already set to rise this year, and that the law is collapsing under its own weight. “Obamacare is a disaster,” Trump said Thursday during an infrastructure event in Ohio. Republicans have also raised the specter of single-payer health care proposals supported by the Democratic base as a way to mobilize Republicans, along with independent voters who could sway some races.

“Democrats destroyed the American health care system as we knew it when they rammed Obamacare down our throats,” said Jesse Hunt, spokesman for the National Republican Congressional Committee. “Now they’ve made support for single-payer health care the litmus test issue in a Democratic primary — ensuring every candidate will have to answer for the $32 trillion disaster they want to enact.”

But the repeal of the individual mandate is expected to further fuel premium increases -- at an inopportune time for Republicans. Additionally, lawmakers have failed to garner approval of a bipartisan plan to continue Obamacare subsidies designed to stabilize the insurance markets. Such a measure was left out of the spending bill signed by the president last week.

Though GOP candidates can try to place the blame on current law and argue that tax cuts will help offset rising health care costs, it’s unclear whether voters will see it that way.

“The preference for Republicans would have been to deal with the ACA, yes, but having the tax bill go through is viewed as a … significant accomplishment and the kind of change they were looking for,” said veteran GOP pollster David Winston. “Having said that, the concerns about premiums and deductibles evolve into a cost-of-living issue, and with over half the country living paycheck to paycheck, any significant increase in the cost of living is going to be noticed. … As those premiums go up, that's going to be challenging to the family budget.”

Winston noted that Republicans’ failure to define a clear alternative to Obamacare resulted in changing opinions of the law, from negative to at least neutral.

“In terms of what the electorate is looking for, they want to understand what you're going to do, not what the other side is doing wrong," Winston said. "One of the clear things Republicans are going to have to do is make sure the people understand [the benefits of the tax bill]. ... It's the responsibility of individual members."