Rubio’s conservative bona fides is doubted by few, but they are an influential minority. One of Rubio’s recent pronouncements ought to allay their fears about the senator’s instincts. “One of the things I’m going to do on my first day in office: I will announce that I am a supporter, and as president I will put the weight of the presidency behind a constitutional convention of the states so we can pass term limits on members of Congress and the Supreme Court and so we can pass a balanced budget amendment,” Rubio told a crowd at an Iowa rally this week.

The notion that Americans should convene a Convention of States pursuant to Article V of the Constitution in order to pass a selection of narrowly-tailored amendments to the nation’s founding charter has some powerful advocates. Chief among them might be the constitutional scholar, author, and radio host Mark Levin. “Rubio endorses Convention of States!” the talk show host exclaimed. “Will the other GOP contenders support it as well?” As a political maneuver, Rubio’s latest is a deft one. Hardened by influential talk show hosts who have spent months inveighing against his support of a 2013 immigration reform bill, Rubio will need to soften the beaches of conservative opposition to his candidacy if he is to win the GOP nomination. This latest proclamation goes some way toward achieving that end. It is also a dangerous pander to one of the right’s worst ideas.

There is a peculiar irony to the fact that a constitutional Convention of States is viewed so favorably by those conservatives who are convinced their side of the political fight does nothing but lose. Moreover, it is a risky approach to amending the Constitution beyond the existing process, which demands overwhelming consensus and years of tempering consideration. Convention proponents don’t seem to see much risk in this process.

Those who are not possessed of infinite faith in their powers of persuasion contend that the Convention of States cannot “run away” from the initial intentions of the conventioneers because some state legislatures will impose penalties on delegates who deviate from the approved agenda. In this way, convention backers claim, only the constitutional amendments conservatives favor – a Balanced Budget Amendment and term limits for federal officials – can be passed and, eventually, ratified. As of today, however, only three states have approved “delegate limitation” or “faithful delegate” acts. Just seven more states have proposed such acts. Further, of the over 30 states that have called for a convention, many did so in the 1980s when the political makeup of the Union was much different. Some of those states have since rescinded their support for a Convention of States, reducing the number of states supporting a convention to as few as 23. This should tell conservatives who support this item something about the nature of competing interests and the rapid pace at which popular sentiment can evolve. To induce more states to call for a convention, the scope of such a gathering would have to broaden substantially.

Contrary to popular belief, there are no rules for such a convention. Congress has tried on over 20 occasions to craft a uniform set of rules governing a convention process, but it has failed every time. The Congressional Research Service cannot definitively assert that a constitutional convention can have a limited focus, and its review of precedent seems to reinforce the notion that a sovereign convention of the people enjoys broad autonomy from state and federal legislatures. Despite frequent assertions that a “runaway” convention is simply not possible, there are no guarantees that conservative delegates can maintain total control over such a radical process. By design, a convention to reconsider the existing amendments, including those in the Bill of Rights, will have an expansive agenda. Conservatives might be surprised to learn that their liberal colleagues are fully empowered to litigate their own grievances with America’s governing charter. And everyone has a problem with the Constitution.

Bernie Sanders liberals are disgusted by the First Amendment’s freedoms as defined by the Supreme Court that overturned the McCain-Feingold campaign finance reform laws. They introduced a new amendment to the Constitution in the Senate that would rewrite the First just last year. Democrats, in general, have for decades sought to limit the freedoms in the Second Amendment, and a recent series of judicial impediments to doing so render the amendment process the best vehicle for enacting far-reaching gun control laws. One ill-timed incident of gun violence amid a convention might foment the rise of a movement in support of such a measure. Libertarians would surely like to strengthen elements of the Fourth Amendment to prevent agencies like the National Security Agency, the Transportation Safety Administration, and the Defense Department from pursuing present methods of information collection and retention. Conservatives of the Levin school would not be happy with a narrow convention agenda that declines to repeal the 17th Amendment, allowing for the direct election of U.S. senators. Further, some hope to draft an amendment that would allow a three-fifths vote of Congress or state legislative bodies to overturn Supreme Court verdicts – eliminating another check on majoritarian governance the Founders, in their wisdom, imposed on posterity.

When the convention ever gets around to considering a Balanced Budget Amendment, media scrutiny of that provision would soon render it toxic. The center-left press would soon discover that America’s largest debt drivers are entitlements, but also sprawling executive branch agencies like the departments of energy, education, and transportation. Does anyone imagine that in today’s polarized age Democrats would sit on their hands while conservatives unilaterally threatened the government’s ability to fund those initiatives? In order to secure liberal support for a BBA, it might be subject to unforeseen revision.

Some convention supporters display unique faith in the tempering power of the ratification process. Any amendments sent to the states out of this convention must be ratified by three-fourths of the Union, therefore only the most popular provisions will be adopted. Amendments 16 through 18, however, granted substantial powers to the federal government and were broadly popular at the time of their ratification. Those who opposed prohibition bowed to popular pressure and agreed to a provision that would sunset the amendment if it was not ratified by three-fourths of the states within seven years of its passage by Congress. They were shocked when it was adopted by a sufficient number of states in just under 13 months.

“Having witnessed the difficulties and dangers experienced by the first Convention, which assembled under every propitious circumstance, I should tremble for the result of a second, meeting in the present temper of America and under all the disadvantages I have mentioned,” wrote the Constitution’s father, James Madison, in 1788. Ever the visionary, Madison’s warning about the “temper of America” is as prudent today as it was prescient nearly 230 years ago. The divine genius of the Constitution, which has made the United States history’s longest enduring republic, is in the charter’s unresponsiveness to the capricious public. If the Constitution is proving too difficult to amend to the tastes of one modest cohort of American voters, it is performing precisely as designed. This is a marvel to celebrate, and “constitutional conservatives” should be doing just that. Instead, they lament their own impotence. In doing so, they forget that their political opponents are limited by precisely the same constraints.

An educated man with a demonstrated reverence for both the nation’s governing documents and America’s founding principles, Marco Rubio likely knows all of this. That’s precisely what makes his latest pander so profoundly disappointing.