Health care will be among the top agenda items for the Democrats as they take control of the House of Representatives.

But just as Republicans couldn't coalesce around a plan to replace Obamacare when they ran Congress in 2017, Democrats are divided about how to address the costly and complex problem of health care as the landmark Democratic health care law comes under renewed attack in the courts.

That lack of unity will be on full display as the party enters the 2020 presidential primary season, with health care expected to play a central role in the campaign to deny President Donald Trump a second term.

Defending the Affordable Care Act

Likely among the first things Democrats will tackle, once the government re-opens: Shoring up Obamacare.

A Texas district court judge declared the landmark health reform law unconstitutional earlier this month, siding with a coalition of Republican-led states challenging the Affordable Care Act. The judge formally ruled Sunday that Obamacare will remain in effect pending an appeal from California and other Democratic states.

Defending Obamacare's protections for those with pre-existing conditions helped the Democrats retake the House in the midterm elections. The provisions -- which bar insurers from denying consumers coverage or charging them more because of their health history and require carriers to offer comprehensive policies -- have become among the most popular of the Affordable Care Act.

Incoming Ways and Means Committee Chairman Richard Neal has repeatedly blasted the GOP for trying to "sabotage health coverage." The Massachusetts Democrat has promised to move quickly to cement the health reform law's pre-existing conditions measures, which could make Republicans lawmakers squirm to support.

"House Democrats will do whatever it takes to make sure the protections enshrined in the Affordable Care Act endure," Neal said in a statement released with Reps. Frank Pallone of New Jersey and Bobby Scott of Virginia. "The lives and wellbeing of millions of Americans -- including those living with pre-existing conditions -- are on the line."

Just what he plans to do remains to be seen, however. In March, the three lawmakers introduced a bill that would have made Obamacare's premium and cost-sharing subsidies more generous and allowed more people to qualify for them. It would have provided more funding for enrollment marketing and outreach and would have prevented the Trump administration from expanding alternative policies that don't have to follow all of Obamacare's rules.

Supporting "Medicare-for-all"

Neal has also said he's open to holding hearings on "Medicare-for-all," a form of single-payer health care. There's likely to be much attention and activity on this controversial idea -- though it has no hope of passing in the Republican-controlled Senate, much less getting signed into law by President Donald Trump, who has openly bashed the concept

At least 70 representatives belong to the Medicare for All Congressional Caucus, which was launched in July by Rep. Pramila Jayapal of Washington, Rep. Keith Ellison of Minnesota and Rep. Debbie Dingell of Michigan. The vocal group of Democrats plans to make sure the concept remains top of mind in the new Congress.

Jayapal plans to introduce a revised bill in the next Congress and plan to push for a debate.

"We can actually have a debate and the American people can decide if it's a crazy, radical idea or if they want their elected representatives to actually make this happen," Jayapal told Politico's Pulse Check podcast in early December.

These House Democrats will have an even bigger bullhorn in Sen. Bernie Sanders, the Vermont independent and champion of Medicare-for-all. Sanders' plan calls for creating a health insurance program that would be run by the federal government and would cover all Americans, supplanting today's job-based policies that cover roughly half the nation. The effort, which would roll out over four years, would cover all medical care, as well as dental and vision with no premiums and few out-of-pocket expenses. The bill Sanders released in 2017 called for consumers to pay up to $250 for prescription drugs.

Sanders acknowledges his plan would be pricey -- in the trillions of dollars range -- and involve raising taxes on businesses and people. But he says Americans would still come out ahead because they would no longer have to pay premiums, deductibles or co-pays.

However, at least one influential Democrat doesn't think the Medicare-for-all movement will go far in the new Congress.

"I've always been an advocate for a single-payer system, but, you know, the votes aren't there," New Jersey Rep. Frank Pallone told the Asbury Park Press in early December. "So I think we really have to concentrate on trying to stabilize the Affordable Care Act, or Obamacare, particularly since the Trump administration is consistently trying to sabotage it."

Buying into Medicare instead

Another set of proposals that don't go quite as far are the Medicare buy-in bills, which have various iterations in the House and Senate. These would let younger Americans purchase entry into Medicare, which currently insures nearly everyone over age 65.

One bill, sponsored by Democratic Rep. Brian Higgins of New York, along with Reps. John Larson and Joe Courtney of Connecticut, would open Medicare to those as young as 50 who don't have access to coverage from their employers or the government. Consumers who qualify for Obamacare's subsidies could use them to help pay for the premiums.

Unlike Medicare-for-all, Higgins said his bill wouldn't cost the federal government a dime since people would pay their own way. But their premiums would be 40% less than a gold-level plan on the Obamacare exchanges.

In exchange for Higgins supporting Minority Leader Nancy Pelosi's bid to reclaim the speakership , she promised him a "good faith effort" to get the bill through the incoming Congress, he said. Neal has also been supportive and promised hearings "very soon," according to Higgins.

"The creation of a brand-new, all-public health insurance system will take time to approve, design and fund," Higgins said. "We can do this now to help a demographic that needs protection now."

Lowering prescription drug prices

There's one issue that both Democrats and Republicans agree on: lowering the cost of prescription drugs. Lawmakers on both sides of the aisle -- as well as the Trump administration -- have tried to address this problem.

House Democrats are expected to take up this issue, but put more of the focus on drug manufacturers' high list prices. Nancy Pelosi, who is expected to become House speaker, pledged just after the midterms that lower drug costs would be a top priority.

Maryland Rep. Elijah Cummings, who will chair the House Oversight and Government Reform Committee, has already promised to hold hearings on drug costs. Cummings, along with Reps. Lloyd Doggett of Texas and Peter Welch of Vermont, introduced a bill in the summer of 2018 to allow Medicare to negotiate drug prices, which many Democrats argue is a way to lower the bill. It has more than 100 co-sponsors.

"There are a lot of people, sadly, who cannot afford the medicine that are being prescribed by their doctors," Cummings recently told CNN's Lauren Fox. "That's a life and death situation. So that would have some urgency to me."