Washington (CNN) Obamacare is facing its next big court challenge this week, but regardless of what the judges decide, President Donald Trump has already succeeded in hobbling the landmark health reform law.

Trump has been trying to dismantle Obamacare from the first day he took office. Hours after his inauguration, he signed an executive order directing agencies to interpret regulations as loosely as possible and to minimize the financial burden of the law through waivers, exemptions or delays.

But after the Republican-controlled Congress failed to repeal Obamacare in 2017, Trump unleashed a series of executive changes to further undermine the law.

Trump has repeatedly said his administration would unveil a plan to replace Obamacare, though Republican senators have distanced themselves from that promise. He told ABC News in June that he'll release a plan in the next two months.

The Republican Party will become the Party of Great HealthCare! ObamaCare is a disaster, far too expensive and deductibility ridiculously high - virtually unusable! Moving forward in Courts and Legislatively!

Now, the Department of Justice is joining a coalition of 18 Republican attorneys general and others who are arguing this week before a panel of three appellate judges in New Orleans that a district court judge in Texas was correct when he found Obamacare unconstitutional in December.

Here are five other things the President has done to the Affordable Care Act:

Made it harder to sign up: Trump cut the Obamacare open enrollment in half, giving Americans only six weeks to pick insurance policies. He has also Trump cut the Obamacare open enrollment in half, giving Americans only six weeks to pick insurance policies. He has also slashed funding for advertising and for navigators, who are critical to helping people sign up. At the same time, he's increased the visibility of insurance agents who can also sell non-Obamacare plans.

Broadened access to alternative plans: The President signed an The President signed an executive order in October 2017 making it easier for Americans to access alternative policies that have lower premiums than Affordable Care Act plans -- but in exchange for fewer protections and benefits.

They include short-term plans. Trump officials lengthened their duration to just under one year, from three months. These plans are typically cheaper, but can also turn down people with pre-existing conditions or charge them higher premiums.

The administration also made it easier for small businesses or some self-employed people to band together to buy so-called association health plans, though this rule is on hold while it works its way through the courts.

Made enrollees pay more: Obamacare enrollees will find they have to pay more for health care and health coverage in 2020 because the administration is changing how some of the law's provisions are adjusted every year. That move means policyholders will have to pay 2.5% more out of pocket than they otherwise would have -- a change that would affect those in large-employer plans too, according to an Obamacare enrollees will find they have to pay more for health care and health coverage in 2020 because the administration is changing how some of the law's provisions are adjusted every year. That move means policyholders will have to pay 2.5% more out of pocket than they otherwise would have -- a change that would affect those in large-employer plans too, according to an analysis by the left-leaning Center on Budget & Policy Priorities.

At the same time, it will make the federal premium subsidies a bit less generous, saving the federal government roughly $1 billion annually for the next few years. But the administration says the changes will also lead to a decrease in enrollment by 70,000 people.

Also in 2017, Trump stopped funding subsidies that help reduce deductibles and out-of-pocket costs for low-income Obamacare enrollees, prompting insurers to raise premiums to cover the loss of these cost-sharing payments

Let states alter Obamacare: The Trump administration last year told states that they could apply for waivers to make more The Trump administration last year told states that they could apply for waivers to make more substantial changes to their Obamacare marketplaces, including altering the rules for who is eligible for federal help paying monthly premiums. These premium subsidies are essential to keeping Obamacare functioning, experts say.

Required Medicaid recipients to work: Some 12.7 million Americans have gained coverage under Medicaid expansion, which broadened eligibility to all adults up to 138% of the poverty line, or about $17,250 for 2019. Some 35 states and the District of Columbia have opted to expand their programs.

But for the first time since Medicaid was established a half-century ago, the Trump administration is allowing states to require certain Medicaid enrollees -- particularly those who gained coverage under Obamacare -- to work in order to continue receiving benefits. Roughly 18,000 Arkansas residents were removed from the rolls last year before a federal judge put the federal approvals on hold.

Despite all of the President's actions, Obamacare has proven surprisingly resilient. Some 8.4 million people signed up on the federal exchange for 2019. Still, that's down from roughly 9.2 million who picked plans for 2017. Much of the drop stems from fewer new consumers selecting policies.