Imagine that you have a life-threatening disease and have run out of available treatments. You discover that there is a promising new medication that might work, but it is still undergoing testing. Would you want the right to try it?

If so, you're in luck, because you have that right, and it has existed since the 1980s under a program known as compassionate use. To exercise it, your physician certifies that there is no comparable alternative and then requests approval from the U.S. Food and Drug Administration. The FDA implemented a streamlined review process in 2016 and approves more than 99 percent of those requests, usually within four days. If you take the medication, the agency keeps track of any adverse effects to protect you and others who might take the drug.

Despite the program's success, a movement has grown over the past several years to cut the FDA out of the process.  Almost 40 states have passed "right-to-try" laws that allow patients to request experimental drugs directly from manufacturers. However, federal drug safety legislation preempts these laws, so they have had little practical effect.

In response, Congress, with strong support from President Trump, recently passed a federal right-to-try law that allows patients with a life-threatening disease or condition to request an experimental drug directly from the manufacturer without first going through the FDA.

What would the new federal law do for patients with terminal conditions? Absolutely nothing. In fact, it could cause them serious harm.

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The law would allow patients to request drugs that have passed the first of three phases of clinical testing. That phase looks for safety concerns in a handful of subjects, sometimes as few as a dozen. It does not include any consideration of a drug's effectiveness. More than two-thirds of drugs that pass phase one fail in the second phase, which does look at effectiveness, and more fail in the third. The chance that a drug will be shown safe and effective enough for use in actual medical practice after passing only phase one is less than one in six.

Many drugs that fail the testing process turn out to be not just ineffective but also dangerous. Some can make the underlying condition worse. The right-to-try law's end-run around the FDA makes it difficult for the agency to monitor those risks. And it removes the patient's physician from the equation, eliminating the traditional front-line of patient protection. What's more, manufacturers are shielded from liability for most adverse effects.

Even after a request is made, a manufacturer is not required to supply the drug. In fact, it may have little interest in doing so. Right-to-try requests can pose a significant administrative burden and a distraction from the more pressing job of completing clinical trials as quickly and effectively as possible. Right-to-try requests could also siphon away the limited supply of experimental drugs that are needed for those trials. Manufacturers are also free to charge for the drugs at a price that may be unaffordable and that is not covered by insurance.

These concerns are why the law is opposed by 100 patient advocacy organizations, including the American Cancer Society, and numerous medical organizations. The main pharmaceutical industry association, the Pharmaceutical Research and Manufacturers of America, has expressed concern that eliminating FDA oversight of right-to-try requests could jeopardize patient safety. Even Scott Gottlieb, the Trump-appointed head of the FDA, has expressed strong skepticism.

Who supports the federal "right-to-try" law? Its main proponent is the libertarian Goldwater Foundation, which opposes most forms of government health and safety protection. It sees the law as a first step in a broader campaign to limit the FDA's authority to protect the public.

It would be nice to live in a world in which oversight of health and safety by a government regulator is not needed for drugs and other medical interventions. Unfortunately, bitter experience over several decades with dangerous drugs and treatments has shown that we do not live in that world and are not likely to anytime soon. FDA regulation to prevent a repeat of those disasters has saved countless lives and prevented untold suffering.

The new "right-to-try" law threatens serious harm to vulnerable patients. And it cruelly encourages false hope in unproven treatments. Patient lives should be too important to let Ideology play around with.

Robert I. Field, JD, MPH, PhD, is professor of law and public health at Drexel University and is the founder and editor of the Health Cents blog.