In attacking recent court decisions on gay marriage, Alabama Chief Justice Roy Moore told reporters, “The moral foundation of our country is under attack. Government has become oppressive.” He went on to urge the nation’s governors to push back by asking their state legislators to call for a convention to amend the U.S. Constitution. Moore is in good company. Faced with issues like balancing the federal budget, protecting gun rights, preserving state prerogatives in health care and insurance, and deciding who gets to marry whom, at least 20 states have already joined the “convention campaign.”

One of the last pieces of the Constitution that James Madison proposed in 1787 was how to keep the document alive. He was very conscious of the uneasy compromise he and his colleagues were trying to frame throughout the Constitution, and he wanted to make extra sure that there was procedural room that would allow the document to bend without breaking. He was especially conscious of the need to balance national with state power, since the convention in which he was sitting had been called by the states because the Articles of Confederation had crumbled.

So Madison created Article V, which allowed Congress to propose amendments to the Constitution. But it also allowed states—if two-thirds of state legislatures agreed—to call for a convention as well. That, he thought, would allow a bottom-up check on top-down government.

The top-down amending process has been used 27 times, but there has never been an Article V convention called by the states. In fact, for the country’s first century, it was barely tried. In the 20th century, however, concerns about the growth of federal power led to 697 state petitions, but only a 1980s attempt to force a balanced-budget amendment came close, with 32 of the 34 needed petitions. The amendment movement died down again until recently, when fierce tensions between the Obama administration and the conservative right sparked a fresh campaign to rein in federal power.

Leading the charge is the conservative American Legislative Exchange Council (ALEC), which has produced a handy manual for state legislators and which held a December conference that debated everything from term limits for members of Congress and the U.S. Supreme Court to a congressional override of Supreme Court decisions.

But because Article V is so brief, no one knows what will happen if a constitutional convention ever convenes. Does a state petition for a convention last forever? (Probably not—the consensus is that resolutions expire after seven years.) Do all state petitions need to call for a convention on the same issue, or is it enough for 34 states to call for a convention on, say, different issues? (They probably have to be on the same issue, most scholars agree.)

Then there is the toughest problem. Would a convention be limited to the issue on which it’s called, or is the agenda up for grabs? Could a convention called on federal budgeting or term limits for federal officials include campaign finance reform? Constitutional scholars disagree, and there’s frank conversation about the risks of a “runaway convention.” Convention proponents point out that the states can block any proposal they don’t agree with, since a convention could only propose amendments to the Constitution (any amendment requires ratification by three-fourths of the states).

But no one really knows what a convention can and can’t do, or how it would work. And if a convention happens, there will be a huge public debate about the very foundation of American democracy itself. That’s surely healthy—and enormously unpredictable.

Meanwhile, some liberals believe they could steer a convention to advance their own issues, even if it came about through ALEC’s strategies. They’d love to overturn the Supreme Court’s Citizens United decision on campaign finance and change the principle of corporations as legal “persons.” Progressives are also convinced that there would be “intrinsic civic value” in encouraging the sort of citizen engagement that might be inspired by a convention, as one spokesperson put it. In fact, some forces on the left are quietly rooting for a grassroots conservative movement so they can slide their own agenda onto the convention floor.

And there’s the rub for the convention debate. Liberals are concerned that the conservatives could amend the Constitution to beat back the role of government. Conservatives aren’t sure they could keep liberal amendments off the table. No one knows just how a convention would work, how long it would last, what rules would guide debate and amendments, or what unexpected pieces might emerge.

Advocates of a convention keep tip-toeing up to the door, but the huge uncertainties have been keeping the last states from taking the jump into the vast unknown. The Article V debate, however, does provide a good barometer on the divisions in the American polity. And it also provides a reminder of just how fine a fabric the founders wove 227 years ago when they put the Constitution together—and how edgy partisans on all sides are about pulling threads that might unravel the basic compact. Democracy isn’t for sissies; Madison and his colleagues made sure that it would always be a full-contact sport.