A Timeline of the Affordable Care Act

A History of Obamacare Health Coverage and the Insurance Marketplace

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The Patient Protection and Affordable Care Act (ACA), also known as Obamacare, has changed how health care is provided in the U.S.

Learn the health insurance enrollment deadline under Obamacare, plus a timeline of the ACA's history and efforts to block it.

Key Takeaways

  • Open enrollment for ACA plans runs from Nov. 1 to Jan. 15 each year.
  • The Patient Protection and Affordable Care Act was signed into law in 2010, helping families and small businesses afford health insurance.
  • Beginning in 2013, the ACA raised taxes on incomes over $200,000 as well as capital gains, rents, and royalties to help cover subsidies.
  • Although the ACA initially imposed a penalty tax for not having insurance, that tax was removed in 2019.
  • Various Republican attacks on the ACA were struck down in court, including a 2021 rejection by the U.S. Supreme Court.

The Enrollment Deadline You Need to Know

The open enrollment period is Nov. 1 to Jan. 15 each year. Coverage begins on Jan. 1 if you enroll by Dec. 15 and have paid your first premium.

The health insurance exchanges make it easy to get Obamacare in four simple steps: create your account, apply for coverage, pick a plan, and enroll.


Even though the Tax Cuts and Jobs Act eliminated the penalty for not having insurance, it's still a good idea to financially protect yourself from unexpected accidents and health crises.

If you miss open enrollment, you may still be eligible to enroll in a health insurance plan outside of the enrollment period. You can still sign up if you qualify for special enrollment due to a major life change such as:

  • Getting married
  • Having a baby
  • Losing other coverage

If you qualify for the Children's Health Insurance Program (CHIP) or Medicaid, you can enroll at any time, not just during open enrollment.

The History of Obamacare

The provisions of the ACA were phased in over several years to allow states and insurance companies time to prepare. Soon after being signed into law, the ACA came under attack by Republicans who believed it to be universal health care.

Here is a timeline of the ACA's phase-in along with attempts to sabotage and overturn it.

June 17, 2021

The Supreme Court threw out the 2018 challenge by 18 Republican state attorneys general and the Trump administration, who sought to declare the ACA unconstitutional. The Court held that because there was no harm or injury traceable to the health insurance mandate, which now held no penalty for enforcement, there was no need to strike it down.

Dec. 20, 2019

Congress eliminated three ACA taxes with H.R. 1865. This canceled the medical device tax that had been paid since 2013. The Joint Committee on Taxation (JCT) estimated this cancellation would cost almost $25.5 billion in lost revenue between 2020 and 2029.

Congress also eliminated the 40% excise tax on businesses that offer "Cadillac" health insurance plans. These high-cost plans offer exceptional coverage, such as small copayments or marriage counseling. They also cover those with high levels of health needs.

Impacted companies include those with a large percentage of employees who are elderly or chronically ill, as well as some with workers in high-risk professions. The tax was to go into effect in 2022. The JCT estimated its elimination would cost $197 billion in lost tax revenue by 2029.

Congress also canceled the annual fee imposed on health insurance providers beginning in 2021. The JCT estimated that would cost $151 billion in lost taxes.

Feb. 26, 2018

Republican attorneys general from 18 states filed a lawsuit to overturn the ACA. They claimed that since the Tax Cut and Jobs Act eliminated the tax on those who didn't have insurance, then the rest of the ACA was unlawful.

The U.S. Department of Justice agreed with the plaintiffs but stayed the decision. Normally, the federal government defends its own programs and laws.

Oct. 12, 2017

President Donald Trump signed an executive order expanding access to health insurance plans that didn't conform to ACA mandates.

June 25, 2015

The Supreme Court ruled that the federal government could distribute ACA subsidies through a federal exchange in states that did not set up their own.

The ACA specifically mentions subsidies should only go to exchanges "established by the state," even though the writers said that was not their intention. The Supreme Court stuck with the intent, not the wording, of the law.

March 31, 2014

The initial period of open enrollment closed. Everyone had to have health insurance coverage for nine months or pay taxes of 1% of their income in 2014. This penalty was eliminated in 2019.

Oct. 1, 2013

The initial open enrollment period began. Those with incomes up to 400% of the poverty level received subsidies to offset the cost of insurance plans purchased on exchanges.

All plans listed on exchanges must have covered the 10 essential health benefits. Medicaid benefits were extended in most states to those with incomes up to 138% of the federal poverty level.

Jan. 1, 2013

Obamacare tax changes kicked in. Those who made more than $200,000 ($250,000 for couples) paid higher taxes. That included 3.8% Medicare taxes on dividends, capital gains, rent, and royalties and 2.35% (up from 1.45%) Medicare taxes on income.

Businesses that manufacture or import medical devices were required to pay a 2.3% medical device tax. This tax was put on moratorium after 2015 and repealed in 2019.

June 28, 2012

The Supreme Court upheld the constitutionality of the ACA's individual mandate that required people to either have insurance or pay a tax penalty. It also ruled that the federal government could not require states to expand Medicaid.

Jan. 19, 2011

The Republican-controlled House voted to repeal the law. That was largely symbolic since the Democratic-controlled Senate rejected a similar repeal proposal by Republican Senators.

June 17, 2010

Federal regulations allowed some health plans that were in existence on March 23, 2010, to be "grandfathered in." That meant they were exempt from the provisions of the Affordable Care Act. It allowed people to keep their current plan if they liked it.

March 23, 2010

President Obama signed H.R. 3590: the Patient Protection and Affordable Care Act. H.R. 4872, the Health Care and Education Reconciliation Act of 2010 (Reconciliation Act), was signed on March 30. Together, these laws are commonly referred to as the ACA or Obamacare.

A Timeline of How Obamacare Came to Be

Follow the twists and turns back through the different bills proposed by the House and Senate in 2009, ending at the beginning: Obama's original campaign proposals in 2008.

March 22, 2010

The House of Representatives passed H.R. 4872: the Health Care and Education Reconciliation Act of 2010. The Reconciliation Act amended the Senate's H.R. 3590 by including elements of the health care plan put forth by President Obama on February 22. 

It kept a state-regulated insurance exchange and cut back taxes on high-end health plans. It increased the Medicare payroll tax on upper-income earners and added Medicare taxes on investment income.

Those with pre-existing conditions who had been denied coverage would also get access to temporary health insurance coverage until the exchange was set up.

Feb. 22, 2010

Obama launched a new health care plan that combined the best elements of the Senate and the House health care reform bills. Like the Senate bill, it eliminated the public option. Instead, it created an exchange that allowed families and small businesses to shop for private insurance plans. Like the House bill, it cut back taxes on the high-end "Cadillac" health plans and eliminated the Medicare gap in prescription drug coverage.

Jan. 28, 2010

Obama urged Congress to pass health care reform in the 2010 State of the Union Address.

Dec. 24, 2009

The Senate passed H.R. 3590: the Patient Protection and Affordable Care Act. It offered subsidies to families and small businesses to shop for insurance on an exchange. It fined companies for not providing insurance but gave tax credits to small businesses to help them afford health insurance for their employees.

Nov. 7, 2009

The House of Representatives passed H.R. 3962, which:

  • Proposed a government-run health insurance program, known as the public option
  • Offered direct subsidies to uninsured people to help them buy insurance through exchanges
  • Proposed a surtax on high-income earners.

As a result, H.R. 3962 would have reduced the deficit by $138 billion over 10 years.


During the presidential campaign, Obama announced the Health Care for America Plan. The most controversial element was known as the "public option."

This would establish a national health insurance plan similar to the plan available to Congress. Opponents said it was socialized medicine. They worried it would take power away from the states and individuals. 

Frequently Asked Questions (FAQs)

Is the ACA still in effect?

Despite numerous challenges, the ACA isn't going anywhere yet. The Affordable Care Act remains in effect after the U.S. Supreme Court rejected an attack for the third time in 2021. That dismissal was the result of a 2018 lawsuit by 18 Republican attorneys general, who claimed the law was unconstitutional. The Supreme Court held that Texas and the other states involved did not have sufficient standing to challenge the law.

When is the deadline for enrolling?

Open enrollment for health insurance purchased on the Marketplace runs from Nov. 1 to Jan. 15. If you sign up by Dec. 15 and pay your premium, your coverage can begin with the new year. If you miss the enrollment period, you can still sign up if you experience a "qualifying life event" such as marriage or the birth of a new baby.

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  1. HealthCare.gov. "4 Steps to Getting Covered in the Health Insurance Marketplace."

  2. HealthCare.gov. "When Can You Get Health Insurance?"

  3. Supreme Court of the United States. "California et al v. Texas et al," Page 1.

  4. Congress.gov. "H.R. 1865 - Further Consolidated Appropriations Act, 2020."

  5. Joint Committee on Taxation. "Estimated Budget Effects of the Revenue Provisions Contained in the House Amendment to the Senate Amendment to H.R. 1865, The Further Consolidated Appropriations Act, 2020," Download PDF.

  6. Center on Budget and Policy Priorities. "Suit Challenging ACA Legally Suspect But Threatens Loss of Coverage for Tens of Millions."

  7. Department of Health and Human Services. "Promoting Healthcare Choice and Competition Across the United States."

  8. Supreme Court of the United States. "King et al. v. Burwell, Secretary of Health and Human Services, et. al."

  9. U.S. Congressman Jeff Duncan. "Full List of Obamacare Tax Hikes."

  10. HealthCare.gov. "No Health Insurance? See if You'll Owe a Fee."

  11. HealthCare.gov. "Affordable Care Act (ACA)."

  12. HealthCare.gov. "Medicaid Expansion & What It Means for You."

  13. Internal Revenue Service. "Affordable Care Act Tax Provisions."

  14. Internal Revenue Service. "Medical Device Excise Tax: Frequently Asked Questions."

  15. Kaiser Family Foundation. "A Guide to the Supreme Court's Decision on the ACA's Medicaid Expansion."

  16. HealthCare.gov. "Grandfathered Health Plan."

  17. Social Security Administration. "The President Signs H.R. 3590, the 'Patient Protection and Affordable Care Act,' and the House passes H.R. 4872, the 'Health Care and Education Reconciliation Act of 2010.'"

  18. Social Security Administration. "The President Signs H.R. 4872, the 'Health Care and Education Reconciliation Act of 2010.'"

  19. Congressional Budget Office. "Letter to Honorable John D. Dingell."

  20. HealthCare.gov. "When Can You Get Health Insurance?"

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