M4A can lead to earlier diagnosis and treatment, potentially saving lives that might be lost under a system where access is dependent on insurance coverage.

A 2009 study estimated that lack of health insurance was associated with 45,000 deaths annually in the U.S. A newer study published in the medical journal The Lancet in 2020 found that Medicare for all would prevent about 68,000 unnecessary deaths per year.

Opponents of M4A argue that a government-run healthcare system could lead to inefficiencies, mismanagement, and lower quality of care, ultimately resulting in higher mortality rates. However, evidence from other countries with universal healthcare systems doesn't support this claim. Notably, these countries spend about half as much per capita on healthcare as the U.S. and get better health outcomes.

The U.S. has a lower life expectancy compared to other wealthy countries. It stands out as a clear outlier on the "Life Expectancy vs. Health Expenditure per Capita" curve, as illustrated in the image below. While an unhealthy lifestyle contributes to this, data also indicates that the lack of health insurance among Americans at lower incomes plays a role.

Opponents argue that lower life expectancy is primarily driven by lifestyle factors rather than a lack of health insurance. However, the key question is whether the absence of health insurance plays a meaningful role—not whether it is the sole factor.