Barring a last-minute political revolt or disaster, the Democratic health-care bill is still looking likely to pass within the upcoming weeks. But even after that happens, Obama’s work to bring health reform to the country will only have begun. David Leonhardt warns of the immense challenges that surround actually implementing the bill’s sweeping provisions. He points out that Obama has yet to nominate anyone to run Medicare, though it’s nearly a year into his administration, and concludes that it’s not a good omen:

Health reform is not merely a matter of passing a bill, hard as that has been (and may still be); its success will also depend on how that bill is put into action…And the lack of a Medicare nomination suggests that the White House is not giving enough attention to what will happen once Mr. Obama signs a bill. Within months, Medicare will need to begin creating pilot programs meant to reduce wasteful care and reward good care. Medicaid will have to plan a huge expansion. The independent Medicare oversight board will have to be formed…When it comes to carrying out health reform, they are already behind schedule.

Leonhardt argues, in fact, that it may have been “cleanest” (and presumably more efficient) to scrap the current employer-based insurance system and start from scratch. But, he says, the political impossibility of such a radical overhaul has left Congress with legislation that instead executes reform by “using hundreds of technocratic tweaks” within “a sprawling, existing organization.” And implementing such changes would be a daunting challenge under any administration.

Other critics may be quick to point out that there’s already massive evidence of fraud and abuse within the current Medicare and Medicaid systems. And there’s concern that the reform bill may only provide more opportunity for criminal and wasteful activity to occur within a system that will be rapidly changing.

To be sure, the Obama administration has demonstrated some concern about making massive programs like Medicare more effective. Concerns about fraud, for instance, have led to new reporting requirements to hold the program more accountable, and the administration has taken greater steps to combat abuses once detected.

But combating Medicare fraud is a targeted, singular effort—tiny in scale compared to reforms on the table. Between the bill’s passage and 2014, when the health exchanges are up and running, it will be a long, hard slog to execute its mandates. It seems too early to judge how successful the Obama administration will be in executing its promises. But Leonhardt is right to lay out the road that still lies ahead.