If you thought the Supreme Court’s decision to uphold Obamacare meant that the national health care debate would cool down, Fortune magazine’s Geoff Colvin offers a different perspective.

The largest issue America will face in 2013 is health care. And it will only get larger. As the national conversation changes, we’ll find that by year-end we’re talking about it all the time, whether the ostensible topic is politics, government, the economy, our jobs, or our families. Health care will be the unavoidable topic.

Medicare and Medicaid are the biggest element of our most serious national problem: crushing federal debt. Washington has evaded the debt crisis for the past two years but can’t do so any longer. The Congressional Budget Office recently projected that “spending on the major health care programs would grow from more than 5% of GDP today to almost 10% in 2037 and would continue to increase thereafter.” Without changes, health care alone will consume more of the federal budget than all discretionary spending does now — defense, law enforcement, courts, and all regulatory agencies. Every time we have to reconcile taxes and spending or approve a federal budget or raise the debt limit, we’ll face the inescapable need to cut Medicare’s and Medicaid’s growth. And every time an elected official whispers such a thing, large groups of citizens will scream.

They’ll yell even louder as 2013 progresses and we all come to grips with the Affordable Care Act. The employer mandate takes effect on Jan. 1, 2014, so companies are deciding what kind of health insurance, if any, to offer employees. We can be certain that some employers who currently offer insurance will find they can save money by dropping it and paying the required penalty.