The Affordable Care Act’s health insurance marketplaces open for enrollment today for the sixth time. But this year the marketplace health plans in many states will face some new competition from insurance products that don’t meet the law’s standards, including the ban on denying coverage or charging more based on a person’s preexisting health conditions.

New Trump administration regulations released earlier this year have undermined the coverage protections in the ACA by making it possible for insurers to renew often skimpy short-term health insurance for up to three years, and for small businesses to form associations that sell substandard health plans. One of the reasons insurers can charge low premiums for these plans is that they generally cover less that ACA-compliant plans and insurers can deny them to people with diabetes or a history of cancer, for example. Only healthy people get these plans. And the more healthy people who buy them, the more expensive coverage becomes for people with a history of illness who buy their own insurance and have incomes too high to qualify for marketplace subsidies. In guidance released last week, the administration will allow states to further encourage the sale of these plans by letting people use federal subsidies to buy them.

As a nation, it is important for us to focus our energy on ways to improve people’s health. We are experiencing an unprecedented decline in life expectancy which will ultimately affect our economic health and the ability of Americans to compete in a global workforce. One of the most basic things we can do is preserve the coverage protections for people with health problems that have been law for more than four years, rather than poke holes in them. Americans say they support this idea. Recent polls have found that majorities of Americans believe that people with health conditions should not be denied affordable health insurance and health care. As a result, House and Senate candidates of both parties are running on their support for protecting coverage for people with preexisting conditions. But some of those very candidates voted to repeal the ACA last year.

The ACA has dramatically improved the ability of people with preexisting conditions to buy coverage. In 2010, before the law passed, we conducted a survey that found 70 percent of people with health problems said it was very difficult or impossible to buy affordable coverage, and just 36 percent said they ended up purchasing a health plan. By 2016, the percentage of people who had trouble buying an affordable plan had dropped down to 42 percent — still high but much improved — and 60 percent ultimately bought a plan.

While the congressional ACA repeal bills failed last year, a Republican Congress could try again next year. And in the meantime, the law’s preexisting conditions protections and other provisions face another threat from a lawsuit brought by Republican governors and attorneys general in 20 states. The U.S Department of Justice has agreed with the plaintiff states in part, and refused to defend the law’s preexisting condition protections. The court decision is pending. Should the states win, an estimated 17 million people could become uninsured.

Some congressional candidates from these states and others are pointing to their support for Republican proposals, such as the “Ensuring Coverage for Patients with Pre-Existing Conditions Act,” as proof they support coverage for preexisting conditions. This bill would prevent insurers from refusing or varying premiums based on preexisting conditions. But, unlike the ACA, this bill would allow insurers to sell plans that entirely exclude coverage for care pertaining to the preexisting conditions themselves. The reality is that this bill would not protect sick Americans, or those who may become ill in the future, from high out-of-pocket health care costs.

Several million people will be going to the marketplaces in the next few weeks to sign up for coverage since they do not have it through an employer. At this time, not one of them who buys a plan in the marketplace has to fear that an insurance company will deny them coverage or charge them a higher premium because of their health. The efforts to undermine the individual market and invalidate the ACA’s consumer protections are real-life threats for people who depend on this insurance for their health care. The nation cannot move forward with tackling our most pressing health care problems if we continue to debate a core protection of the ACA that most Americans support.