It already is. Some of the proposals for universal health care call for mandated health insurance coverage. One would be deprived of the constitutional freedom to reject conventional medicine. When queried as to what the penalties would be for those who refuse to buy the mandated policy, Hillary Clinton demurred, saying that that was yet to be determined.
I think western medicine is first rate with dealing in life threatening acute cases, such as trauma, heart attack, stroke, etc. But for chronic diseases and pain, it is not nearly so efficacious. The problem is that any drug powerful enough to effect cure, is also powerful enough to produce harm (Paracelsus?). With the exception of some natural substance replenishment treatments such as insulin, most drugs are totally foreign, unnatural substances. These chemicals may produce some desirable physiological changes, but almost always produce adverse effects as well. The problem becomes even worse when people take multiple drugs (very common among seniors) with cross drug complications. type I diabetics are diabetic due to an absence of insulin, but the far more common type II diabetics are not diabetic as a result of metformin or actos deficiency. Type II diabetes can be easily treated by non drug means, but the treatment requires much more time and monitoring by a physician than simply prescribing a drug and referring a patient to a manual dealing with diet and exercise. The diets recommended are usually precisely the diets that cause diabetes. For many chronic conditions, the best investment possible, may be a comfortable pair of walking shoes, but the patient will get one or more prescriptions instead. I recently saw a study that suggested that much of senility noted in seniors, may in fact, be complications of prescription drugs.
Many drugs, in fact, are prescribed precisely because they do interfere with the body's natural defenses. People who have colds, take prescriptions to lower fever, decongest them, and suppress coughing. They may be working against their own bodies, of course, they can't go to work, wheezing and hacking. But it's not curative medicine they are taking, but rather, symptom alleviating drugs, which may result in a more serious sickness than would have occurred otherwise.