The new year may have just started, but we already have a good idea of where the big stories in health politics and policy are heading. Below we take a look at the debates that could dominate 2015. And if you missed it earlier, check out our review of 2014’s most important health stories.

A Republican Senate on Obamacare (…and Medicare, Medicaid and the FDA)

One of the biggest stories of 2014—Republicans winning control of the Senate with 54 seats—will play a significant role in determining the direction of health policy and politics in 2015. The immediate focus will be on what the GOP does with the Affordable Care Act, and Republicans are expected to take a symbolic vote to repeal Obamacare early on in the 114th Congress. But it will be tough to get the 60 votes needed to get a repeal bill through the Senate, and President Obama has vowed to veto any such measure. Following that vote, expect piecemeal efforts to repeal the law, undoing provisions like the medical device tax and how the law defines a work week. These smaller changes stand a chance of getting the president’s signature, particularly if they are attached to must-pass bills like funding the government or passing a Medicare physician pay fix.

But Republicans are now in the driver’s seat for a lot more than the Affordable Care Act. They will also set the congressional agenda on Medicare, Medicaid and the FDA. On all three fronts, Republicans, particularly in the House, have built a foundation for major reforms. It is unclear right now how much the GOP will want to wade into a Medicare and Medicaid fight ahead of the 2016 election, but the FDA is one target to keep an eye on. House Republicans on the Energy and Commerce Committee have laid out proposals that could overhaul the agency, and expected Senate Health, Education, Labor and Pensions Chairman Lamar Alexander (R-TN) has signaled he is eager to take on FDA reform.

The ACA Hopes for a Second Life at SCOTUS

If one Supreme Court challenge to the existence of the Affordable Care Act wasn’t enough, 2015 will bring a second case that could gut the law by erasing insurance subsidies for millions of Americans.

The Supreme Court in December announced the case, King vs. Burwell, would be heard on March 4, setting up a decision to be handed down in June. The case questions whether the federal government can distribute insurance subsidies to people in the approximately 34 states that rely on the federal government to run their exchanges. Conservatives generally say the law only explicitly allows subsidies in exchanges set up by states. Democrats, including those who drafted the law, say the language in question is simply a drafting error.

In the balance hangs insurance subsidies for about 5 million people who will see significant increases in cost without federal help. So far, states haven’t done much to prepare for the possibility that their residents will lose funding if the Supreme Court rules against distributing subsidies via federal exchanges, as Margot Sanger-Katz reports for the New York Times. And at a December press conference, Health and Human Services Secretary Sylvia Burwell would not say directly if the agency was drawing up contingency plans for a ruling against the Obama administration. Both are questions that will crop up for states and the federal government in the coming months.

The Health Care Cost Slowdown Saga

Health care costs slowed in 2014, declining to the smallest year-over-year increase in federal and private health spending since the government started tracking the figures in 1960. It also marked the fifth straight year of declines in the rate of health spending. But in 2015 the cost of approximately 7 million more people having health insurance, thanks to the Affordable Care Act, will show up in many estimates of health spending for the first time. Massachusetts’ earlier experience with broadly expanding insurance coverage showed that giving more people insurance led to an increase in health spending, and the same could be seen on a national level this year. Despite potential increases, expect continued debate over whether the slowdown in health costs was a lingering effect of the economic recession or has been prodded along by the Affordable Care Act.

Beyond economic discussions, mergers and acquisitions in the health industry will likely continue, as providers and payers team up (or work against one another) to figure out how to provide and insure healthcare at a cost that ensures they’ll still have paying customers. In Medicare, 89 organizations are slated at the start of 2015 to join a program that aims to get providers to improve coordination and take on financial risk to reduce government costs. But with many contracts ending in 2015, the bulk of participants will be deciding if they want to continue in the Medicare “shared savings” program. And while many organizations reported improved quality, actually seeing cost savings has been more elusive, reports Modern Healthcare.

Morning Consult