In the final days of the Obama Administration, many people are looking back at the legacy the 44th president of the U.S. will leave behind. However, one of the biggest accomplishments of his eight years in office may be undone by a Republican-led battle in Congress.

On Jan. 13, the House of Representatives voted to take the first step in repealing the Affordable Care Act, nicknamed “Obamacare.” However, many Republicans and Democrats alike have concerns regarding the repeal. If the ACA is repealed without an immediate replacement, this will leave over 20 million Americans without health insurance.

According to CNN, House Speaker Paul Ryan vowed to have a replacement for Obamacare at the time of the repeal; however, he provided little specifics on how that replacement will look.

On Jan. 8, Senator Rand Paul unveiled some details of his version of a replacement plan on CNN’s “State of the Union” with Jake Tapper. He mentioned a couple of debated topics that can give us an idea of some of the goals Republicans for their replacement.

Obamacare’s mandates

“One of those key reforms that we will do is, we’re going to legalize the sale of inexpensive insurance,” Paul said to Tapper. “That means getting rid of Obamacare mandates on what you can buy.”

One of the biggest complaints of Republicans with Obamacare is with the mandates that limit the customization of health insurance plans. Obamacare took multiple benefits that were hard to find and required insurers to include them in all of their plans. Those in opposition of the ACA argue that this raises the cost.

Under Paul’s plan, consumers would be able to choose the plan with the benefits that make the most sense for them. A common argument is something along the lines of, “Why should a 55-year-old couple have to pay for maternity benefits?”

By giving consumers more choice, insurers can lower premiums. However, this is likely to raise deductibles.

Health savings accounts

“We are going to help people save through health savings accounts, as well as tax credits,” Paul said.

For these higher deductibles, Republicans encourage people to take advantage of health savings accounts. These accounts allow individuals to set money aside for future medical expenses tax-free.

To be eligible for these accounts, an individual must be covered by a high-deductible health insurance plan. As of right now, according to National Conference of State Legislatures, high-deductible plans are those that require single patients to pay the first $1,300, or families to pay the first $2,600.

Paul also mentioned tax credits as way to help lower the cost for those who need help. Under Obamacare, the federal government provides funding to help pay for insurance based on income. The less you make, the more money you get to help cover the cost of your premium.

Republicans are in favor of these tax credits; however, according to CNN, the Republican plan would base credits on age, not income.

It’s a complicated process

An all-out repeal of Obamacare isn’t likely because of the Democrats’ ability to filibuster the vote. Republicans, instead, have to take a different route.

The vote that took place last week to set the repeal into motion was on a “budget reconciliation.” As Think Progress explains, this vote now allows congressional committees to create legislation around federal spending and, in turn, allows legislation to be created to undo major portions of Obamacare.

This means last week’s vote was only step one, and it was the easiest part of the battle to repeal the legislation. Congress will need to agree on a replacement plan and specific legislation to repeal the provisions. The process will take a long time, and nothing is changing anytime soon.