The Affordable Care Act of 2010 was the most significant expansion of government regulation of our health care system since the passage of Medicare and Medicaid in 1965. Not only does it make insurance less discriminatory toward people with pre-existing conditions, but it attempts to guarantee that every single person in America can depend on having affordable insurance.

Essentially the way the law was originally set up, one way people would get insurance who did not have it previously could be under the Medicaid expansion. With this provision, people below 138 percent of the federal poverty line would be newly eligible for Medicaid insurance. People who were still not eligible for Medicaid or who do not have insurance provided through their employers could buy insurance through the insurance exchanges, which is essentially a marketplace where customers could compare prices and benefits and buy insurance with government subsidies, if they are eligible.

Both the insurance exchange and the Medicaid expansion were mandatory when the law was originally formulated. But when the law went through the Supreme Court, the only provision they struck down was the mandatory Medicaid expansion, instead giving states the option to opt in or opt out.

If states opt in, the federal government will cover the full cost of the expansion from 2014 to 2016, and then after that gradually decrease the federal share to 90 percent of the cost in 2020. If states opt out, then individuals below 138 percent of the poverty line but above the state’s previous income eligibility requirement are left without any insurance. People in this income range — mostly the working poor — are considered too wealthy to apply for Medicaid but too poor to receive assistance paying for insurance through the exchanges.

So far, 25 states have opted in to the Medicaid expansion, and 15 states have opted out. As expected, many of the states that have opted out are traditionally led by a Republican majority, which as of late has been making every effort to keep federal government out of state affairs.

But there have been a few surprises: Arizona, New Mexico, Nevada and North Dakota all opted in to the expansion even though they all have Republican governors. Florida’s Republican governor, Rick Scott, said he supported the expansion, but his legislature struck down his decision.

Tennessee was one of the most recent states to announce its decision to reject the expansion. Governor Haslam came to his decision a week ago, proposing that the state use the federal expansion funds to help people below 138 percent of the federal poverty line buy their own private insurance. Other states are interested in this sort of plan as well, but President Obama has said that any plan that doesn’t cover the all that would be newly eligible under the Medicaid expansion is not good enough.

This private insurance plan certainly wouldn’t cover the same amount of people. Governor Bill Haslam has said his plan would insure 175,000 previously uninsured people in Tennessee. But the Center on Budget and Policy Priorities has shown that if Tennessee were to accept the expansion, 361,000 Tennesseans would be newly eligible for insurance coverage with Medicaid.

The Affordable Care Act wasn’t originally crafted to have an optional Medicaid expansion. When states opt out, they keep an extremely vulnerable group of people from gaining the insurance and health care stability they need to try and make improvements to their socioeconomic status. States can’t complain about money because the federal government is mostly footing the bill. The only real reason to reject the expansion is for political maneuvering, and it’s shameful to sacrifice the well-being of a state’s citizens for it.

— Lindsay Lee is a junior majoring in mathematics. She can be reached at [email protected].