I am worried about the Democratic Party's new focus on Medicare for All.

The merits of the policy are anything but a slam dunk but, more immediately, the politics are a minefield.

When it comes to health care reform, Democrats need to mind three basic rules.

First, experience teaches us that much as Americans hate the status quo, they're not too excited about change, either.

Second, policy is not everything — political communication counts, too.

Third, success ultimately rests with uniting your allies and dividing your opponents.

Medicare for All is guaranteed to frighten many among the vast majority of Americans who already have health coverage. It would require a disastrously unpopular tax increase on the middle class. And it would unite a world of the special interests against us.

This dog just won't hunt. Perhaps worse, we cannot afford to try and then fail. Losing on health care will make it more difficult for us to make progress on education, the environment or other social justice issues. We need to chart a different path. So let's use history and context as a guide.

I'm mystified as to why, at a moment when 90% of Americans already have insurance, our presidential debates are focused so exclusively on expanding coverage rather than containing costs. That's the challenge that bedevils most families constructing their monthly budgets at the kitchen table.

Moreover, let's not forget that the Affordable Care Act represents the only time in a century of trying that universal coverage managed to get a vote on the floor of both houses of Congress. In 2010, we had 58 Democratic senators — yet we weren't even able to get a vote on a public option. Even if we draw a royal flush in next year's election, we'll have only 51 votes.

I believe we ought to work on a more politically palatable agenda, one that builds on the successes we've achieved incrementally by expanding coverage to vulnerable portions of the population — for the elderly (Medicare), the poor (Medicaid), veterans (Veterans Affairs) and children (SCHIP).

How to do it? To begin, let's remind voters that Donald Trump's budget called for the largest cuts in Medicare ever proposed by a U.S. president. Highlighting his plan for "Medicare Cuts for All" should be the table-setter before we explain what we'll do to control costs and expand coverage.

Then, in an effort to build on our previous successes, we should focus on the fastest-growing portion of the uninsured community — the vote-rich demographic of early retirees. Here's a simple fix: Expand coverage by allowing Americans 55 and older to buy into Medicare before they hit 65. Republicans will then be forced either to support an expansion or alienate a crucial electoral voting bloc.

Finally, we should make good on the promise of a true public option by giving private citizens access to the same insurance covering federal employees. Senators, Cabinet secretaries and their family members enroll in taxpayer-subsidized plans that leverage the size of the federal workforce to drive down premiums, copays and prescription drug costs. Opening those rolls to everyone would put the GOP in the uncomfortable position of having to explain why voters shouldn't have access to the same plans they're already purchasing for people being chauffeured around Washington.

The bottom line is that there's simply no path to enacting Medicare for All in the current political environment, and promising something we can't deliver will do nothing but depress Democratic turnout in years to come. Since we're already proposing to rewrite the tax code, decriminalize the border, give everyone free college and eliminate the use of fossil fuels with the Green New Deal — all initiatives that will require us to expend enormous amounts of political capital — maybe we want to be strategic on at least one big-ticket item.

Rahm Emanuel is a former mayor of Chicago, Democratic congressman from Illinois and White House chief of staff. He wrote this article for the Washington Post.