The fate of the GOP’s health reform plan right now hinges on Sen. John McCain’s recovery from a blood clot surgery. The health scare is also the perfect reminder of just how critical insurance can be — and how much protection from medical emergencies Americans stand to lose with the Better Care Reconciliation Act, the Senate Republicans’ plan to dismantle Obamacare.

According to a press release from McCain’s office, the senator had a craniotomy to remove a blood clot from above his left eye on Friday, July 14, at the Mayo Clinic in Phoenix, Arizona. He’s now “recovering comfortably at home.”

This weekend, Senate Majority Leader Mitch McConnell announced that he’d delay the vote on the contentious Better Care Act until the Arizona Republican had returned to the Hill and could vote to start debate on the bill. (McConnell needs all the supportive votes he can get.)

There are at least four deeply ironic things about McCain’s health situation:

1) As Vox’s Dylan Scott explained, nothing less than a health emergency has thrown the GOP’s health reform plan into disarray.

2) The senator’s office is saying the blood clot was discovered during a routine physical, which is exactly the type of preventive service Obamacare expanded and the Better Care Act could curtail.

3) The craniotomy sounds like an emergency surgery (though McCain’s office would not confirm that). Obamacare required insurance plans sold in the individual market, the fully insured small-group market, and through Medicaid to cover a list of 10 “essential health benefits”, including emergency healthcare. The Better Care Act would allow health insurers to once again sell skimpier insurance plans that might not include such comprehensive benefits.

4) Life-saving surgeries like these would also be out of reach for more people if the GOP plan were to pass, since it’s expected to leave millions more Americans without insurance compared to Obamacare.

To find out just how much the procedure would cost someone without insurance, we looked to the Centers for Medicare and Medicaid Services, which publishes Medicare payments for more than 3,000 hospitals for inpatient procedures. We decided to go with the Medicare rate, since this is often used as a benchmark by experts for the cost of a procedure and it’s what the government considers reasonable to pay for a service.*

At the Mayo Clinic in Phoenix (line 1598 of this spreadsheet), the most recent data (2014) suggests the average charge to Medicare for a craniotomy was $76,119, while average Medicare payments ranged from $25,932 to $33,958.

For help interpreting these costs, I called up Jeanne Pinder, the founder and CEO of clearhealthcosts.com. She noted that there’s a lot of variation among hospitals and states in the US, so the charges in Arizona and at Mayo may look quite different than what patients would be asked to pay elsewhere. But she was clear on one thing: an uninsured American would be “very fortunate” to pay the amount Medicare does for its bills. Instead, individuals without insurance would more likely be on the hook for the full $76,000 the hospital bills for this procedure.

The folks at Healthcare Bluebook, another healthcare cost estimating website, also said patients without insurance are typically asked to pay the billed charges at hospitals, which can be two to three times more than the Medicare allowable amount. (We asked Mayo Clinic to confirm the average cost of the procedure and did not hear back. McCain’s office referred us to their press release.)

Obamacare made health insurance plans more robust by requiring insurers to cover a basic array of services for people, including emergency services. Obamacare also helped expand access to insurance through Medicaid, the government health insurance program for the poor, as well as through the individual marketplace. The GOP’s Better Care plan would loosen some of those requirements for basic insurance coverage and roll back the Medicaid expansion, which would leave more people on the hook for their hospital bills and fewer people with health coverage.

That means that if McCain happened to be one of his uninsured or under-insured constituents, and not a Senator with his healthcare subsidized by American taxpayers, he might have had to shell out some $76,000 for his surgery — more than the average annual household income in America.

*Caveat about this price estimate: Finding the precise price of a procedure in America can be an exercise in futility: Different hospitals charge different patients different prices on different days. Also, there’s some question around whether McCain’s office provided accurate information on the details of his health status, and experts think his blood clot might actually be more complicated and serious that the McCain team is suggesting. Hospitals could apply tens or hundreds of billing codes for a complicated episode of healthcare like the one McCain appears to have gone through. That means the cost of a craniotomy alone is probably a conservative estimate of the total bill McCain rang up.