Texas Sen. Ted Cruz and several co-sponsors have introduced a proposed constitutional amendment for congressional term limits. The measure would limit senators to two stints of six years each, and representatives to three periods of two years each. Service for a fraction of a term would be treated as a full term if that fraction is more than half a term.

Of course, the chance that Congress will send this measure to the states for ratification hovers somewhere around absolute zero. With the arguable exception of the 21st Amendment (repealing Prohibition), Congress has not proposed an amendment restricting itself since the Bill of Rights in 1789.

So the only way the states could consider ratifying a term limits amendment would be for a convention of the states to propose it. That would require 34 state legislatures to “apply” for a convention. The legislatures could put term limits on the convention agenda by approving the form applications advocated any of three groups seeking a term limits amendment: U.S. Term Limits, the Convention of States Project, and Act 2.

The sponsors surely understand their measure has no chance in Congress. That may explain why they didn’t take more care in drafting it.

If you are familiar with constitutional drafting, the first thing you notice when you read this measure may be its stylistic oddities. It calls Congress’s tender of an amendment to the states a “submission,” although the constitutional term is “proposal.” (The two may be synonyms, but good legal drafters avoid using different words to mean the same thing.) In addition, the drafters employed Arabic numerals (as in, “1 term,” “2 terms,” and so forth), which is at odds with the uniform style of the Constitution and all previous amendments. The constitutional style is that numbers other than section numbers are spelled out (“one term,” “two terms,” etc.)

But the problems are more than merely stylistic. The portion of the text dealing with senatorial vacancies may be ambiguous. The ambiguity arises in this way: Suppose a senator dies with three years and one month left in his term and the state governor appoints a replacement to fill the vacancy until a special election. The replacement serves for 13 months, and then wins an election to continue throughout the remaining two years in the term. The drafters’ apparent intent was that the two time periods be added together to total three years and one month. Because this is more than half a term, the replacement could run for only one more term.

Yet the amendment’s wording can be construed as saying the replacement served only two partial terms, each under three years, so he may run for two more.

More serious are two provisions that would render state ratification very difficult. The first provides for ratification by state legislatures rather than the constitutional alternative of popularly-elected state ratifying conventions. Many state legislators strongly oppose term limits, even when those limits don’t apply to themselves. Ratifying conventions such as those employed to ratify the 21st Amendment, are far more likely to approve term limits than state legislatures.

Additionally, even term limits proponents may balk at permitting only three terms, or six years, for members of the House of Representatives. Among existing term limits rules, this is an unusually short period: Allowances of eight to 12 years are far more common.

There are several arguments against such a brief tenure. One is that limiting representatives to only six years may put them at a disadvantage compared with the president, who may serve eight years, and compared to senators, to whom this measure permits twelve years.

If the sponsors are serious, they should recommend that the state legislatures apply for a convention for proposing amendments with authority to consider term limits. They also should correct the drafting defects and improve the substance. One creative suggestion comes from the “Act 2” program: Rather than specify different limits for the House and Senate, provide a single maximum for each individual’s service in Congress — perhaps 12 or 18 years. This allows a member of Congress (if duly re-elected) to remain for that entire period in one chamber, or to divide service between the House and the Senate.

Robert G. Natelson was a law professor for 25 years specializing in constitutional law, constitutional history and related courses. He is presently senior fellow in Constitutional Jurisprudence at the Independence Institute in Denver. He has published extensively on the Constitution and is the author of The Original Constitution: What It Actually Said and Meant.