The Affordable Care Act (ACA), also known as Obamacare, is a landmark healthcare reform legislation enacted in the United States in 2010. The ACA was signed into law by President Barack Obama with the aim of increasing the quality and affordability of health insurance, expanding Medicaid eligibility, and implementing various provisions to improve the overall healthcare system. The ACA represents one of the most significant changes to the U.S. healthcare system in recent decades.

Key features and provisions of the Affordable Care Act include:

1. **Individual Mandate:**
– The ACA included an individual mandate, which required most Americans to have health insurance coverage or face a penalty. This provision aimed to increase the number of people with health insurance and promote a larger, more diverse risk pool.

2. **Health Insurance Marketplaces:**
– The ACA established health insurance marketplaces (also known as exchanges) where individuals and families could compare and purchase private health insurance plans. These marketplaces provided a platform for individuals to access coverage and receive subsidies based on income.

3. **Medicaid Expansion:**
– The ACA sought to expand Medicaid eligibility to cover more low-income individuals and families. However, a 2012 Supreme Court decision made Medicaid expansion optional for states, leading to a varied implementation across the country.

4. **Protections for Pre-existing Conditions:**
– The ACA introduced provisions to prohibit health insurance companies from denying coverage or charging higher premiums based on pre-existing conditions. This aimed to ensure that individuals with health issues could still access affordable coverage.

5. **Essential Health Benefits:**
– Insurance plans offered through the ACA marketplaces were required to cover a set of essential health benefits, including preventive services, maternity care, mental health services, and prescription drugs.

6. **Coverage for Young Adults:**
– The ACA allowed young adults to stay on their parents’ health insurance plans until the age of 26, providing extended coverage during a critical period when many individuals are transitioning into the workforce.

7. **Employer Mandate:**
– Large employers (those with 50 or more full-time employees) were subject to an employer mandate, requiring them to offer affordable health insurance coverage to their employees or face penalties.

8. **Preventive Services:**
– The ACA mandated coverage of preventive services without cost-sharing, including immunizations, screenings, and preventive services for women.

9. **Insurance Market Reforms:**
– The ACA implemented various reforms to the health insurance market to enhance consumer protections, improve transparency, and promote fair competition.

The Affordable Care Act has been the subject of political debate since its inception, with both support and criticism. While it has expanded access to health insurance for millions of Americans, some have raised concerns about its cost, impact on insurance premiums, and the role of the federal government in healthcare. Changes to the ACA have been proposed and implemented through subsequent legislation and executive actions.