It’s only a short phrase buried in the U.S. Constitution, but it enables an unprecedented avenue to change the law of the land: If two-thirds of the states demand it, Congress “shall call a convention” for proposing constitutional amendments.

A hopeless pipe dream? Actually, no; the issue is front and center right now. Some 27 states have active calls for a convention on a balanced budget amendment, which would force the federal government to pass budgets that do not enlarge the national debt. This means that theoretically just seven more have to act for a constitutional convention to be called, at least on that subject.

In just the first few weeks of this year's state legislative sessions, at least 10 states have bills pending that call for a convention. So suddenly such a meeting, not held since the earliest days of this country, is becoming a real possibility.

Even GOP presidential candidates are seizing on the burgeoning movement, with Florida Sen. Marco Rubio, former Arkansas Gov. Mike Huckabee and Ohio Gov. John Kasich endorsing this unconventional process and rallying their supporters as legislative sessions start up again.

While the legislation appears to be a grassroots effort bubbling up from the states, in reality it’s quite the opposite. National groups have been holding workshops, publishing tips and even crafting model legislation for years to persuade legislators to use their states to circumvent the logjam in Congress.

The push is led by American Legislative Exchange Council, the Virginia-headquartered conservative think tank known as ALEC made up of state lawmakers and corporations that advocate free-market policies in the states. It has a cadre of other like-minded national allies working on the controversial strategy to revise the country’s supreme laws.

But in a fight reflecting the broader schism within the Republican Party, other national groups on the right such as the John Birch Society and Phyllis Schlafly’s Eagle Forum are combating these efforts with their own legislative push to rescind those calls for what is called an Article V convention. Working alongside unlikely liberal allies, they say the country runs the risk of a runaway convention where delegates could change the complete makeup of the Constitution.

“Once you open up the Constitution to change at a convention, then you can change anything in the Constitution,” said Michael Leachman at the left-leaning Center on Budget and Policy Priorities, a think tank that has written about the dangers of a balanced budget amendment. “It’s theoretically possible.”

How it works

Americans can amend the Constitution in two ways, as laid forth in Article V of the body of laws. The first has been used to pass all 27 amendments that exist today: Congress proposes an amendment with two-thirds majority in both chambers that must then be ratified by three-quarters of the states.

The second route requires two-thirds of states to call a convention for proposing amendments, according to the Constitution.

Besides these few words, the Constitution doesn’t give much more guidance. Lawmakers grapple with how to conduct such a meeting: Who attends? Where is it held? What is the agenda? Who leads the proceedings? What are the rules?

Activists trying to convene such a convention are drawing on historical records to interpret the body of laws for clues on how to pull it off. Based on that limited research, they see two routes to such a meeting.

On one side, ALEC and its allies seek to persuade 34 states to pass resolutions to call the meeting, as well as parallel legislation that outlines the rules and structure of the convention. After the convention delegates meet, 38 states would still need to ratify any amendment that the attendees produce at the convention.

For bills to count toward the necessary 34 applications, though, they must seek the same amendment to discuss at the convention. So far, a balanced budget amendment is the closest to that requirement. But bills have also called for conventions about a cornucopia of issues, ranging from reforming campaign finance to congressional term limits. Critics are concerned that other topics could be introduced once the convention begins.

The other, albeit more unlikely path, wraps up the resolution, rules and ratification in one neat package: an interstate compact. This alternative method requires 38 states to pass the compact package, as well as congressional approval.

This compact strategy still has a long way to go. The group leading the charge, Compact for America, has helped pass bills only in Alaska, North Dakota, Mississippi and Georgia so far. But it also has the backing of ALEC, which posted model compact legislation on its website. And at least four compact bills have been filed to be heard in 2016.

"The founders thought this was a very controlled, moderate, predictable process,” said Nick Dranias, Compact for America's president and executive director. "It was not meant as a red button. Nothing could be more lawless than what we already have going on in Congress."

The Texas-based group has deep ties to the conservative Goldwater Institute in Arizona; its leaders, Dranias and Thomas Patterson, were both formerly top brass there. Compact for America does not disclose its donors for “fear of political retaliation,” according to its tax filings.

The campaign for conventions, however one comes about, is not solely led by a conservative bastion. Former Democratic presidential candidate Lawrence Lessig stands out as a major leader in the movement.

Lessig and ALEC are pushing for different final goals, though. Lessig hopes to overturn the U.S. Supreme Court campaign finance case Citizens United with a constitutional amendment. Still, they have united on using states to overcome congressional stagnation.

"In my view, if you look at American government today, the fundamental stale institution of Congress is crippled by the way congressmen are selected,” Lessig told the Center for Public Integrity. “It produces a widely more polarized Congress than the population. An Article V convention is the only solution the framers gave us."

Critics say the only precedent for a successful convention occurred in 1787 when framers met to discuss weaknesses found in the Articles of Confederation. Instead of tinkering with the articles, the attendees scrapped the whole set of laws for the current Constitution. This context only intensifies critics’ fears of a runaway convention.

“It’s quite clear that any convention would be subject to enormous lobbying pressure,” Leachman said. “This convention is deciding amendments to the Constitution. Any interest group in the country would be very interested in the results of that.”

Convention supporters point to research that suggests states held nearly 20 smaller conventions before 1787 that can be used as guidelines, according to Rob Natelson, a senior fellow at the free-market Independence Institute think tank in Colorado, who wrote ALEC’s handbook on such conventions.

“Essentially, they served as task forces where delegates from different states could share information, debate, compare notes, and try to hammer out creative solutions to the problems posed to them,” Natelson wrote.

Natelson said many safeguards exist to prevent chaos at a convention: legislation that limits the scope of the meeting by attending states, the potential for lawsuits and the required ratification of any proposed amendment. The more pressing worry, he says, is that delegates won’t be able to agree on the fine print of an amendment to fix the issue they’re discussing.

“The more legitimate concern is not that they’ll go wild, but that they won’t cure the problem,” Natelson said. “Getting so many people to agree on wording is difficult and deadlock is probable.”