What about costs? There were many predictions of soaring premiums. But health reform’s efforts to create meaningful competition among insurers are working better than almost anyone (myself included) expected. Premiums for 2014 came in well below expectations, and independent estimates show a very modest increase — 4 percent or less — for average premiums in 2015.

In short, if you think of Obamacare as a policy intended to improve American lives, it’s going really well. Yet it has not, of course, been a political winner for Democrats. Which brings us to Mr. Schumer.

The Schumer critique — he certainly isn’t the first to say these things, but he is the most prominent Democrat to say them — calls health reform a mistake because it only benefits a minority of Americans, and that’s not enough to win elections. What President Obama should have done, claims Mr. Schumer, was focus on improving the economy as a whole.

This is deeply wrongheaded in at least three ways.

First, while it’s true that most Americans have insurance through Medicare, Medicaid, and employment-based coverage, that doesn’t mean that only the current uninsured benefit from a program that guarantees affordable care. Maybe you have good coverage now, but what happens if you’re fired, or your employer goes bust, or it cancels its insurance program? What if you want to change jobs for whatever reason, but can’t find a new job that comes with insurance?

The point is that the pre-Obamacare system put many Americans at the constant risk of going without insurance, many more than the number of uninsured at any given time, and limited freedom of employment for millions more. So health reform helps a much larger share of the population than those currently uninsured — and those beneficiaries have relatives and friends. This is not a policy targeted on a small minority.