The fundamental grammatical error in the Twenty-sixth Amendment is the use of a nonrestrictive clause instead of a restrictive clause.
A restrictive clause cannot be left out of a sentence, whereas a nonrestrictive clause can be."(16) As the Texas Law Review's Manual on Style explains, The author's intention determines the correct usage.
A nonrestrictive clause, on the other hand, refers to the whole group of things represented by the noun--in this case, your cows.
Not all restrictive and nonrestrictivc clauses begin with the relative pronouns "that" and "which." Others begin with the relative pronouns "who," whom, and "whose." Without going into the differences among these words, I'll simply point out that any restrictive clause they introduce has no commas and any nonrestrictive clause they introduce carries the mandatory commas.
* Who may begin a restrictive or
nonrestrictive clause (see also Chapter 31):
restrictive clause--a clause that limits the meaning of a particular word or is otherwise essential to the meaning of a sentence; a
nonrestrictive clause is not essential to the meaning of a word or sentence
I tend to go into paroxysms of editorial exasperation over "hopefully," an adverb that is almost always incorrectly used in speech and writing instead of "it is hoped." A distinction between restrictive and
nonrestrictive clauses, that is, between "that" and "which," is also important to me.
While John and Jane sit in the back row of our classrooms wondering whether they will ever get back their driver's licenses and whether their divorced fathers will send a check this month, we seek their attention to the barely discernible difference between restrictive and
nonrestrictive clauses.
One especially irritating thing is the problem of punctuation, in particular the lack of distinction between restrictive and
nonrestrictive clauses and phrases, evidently suggesting a hurried preparation of the English manuscript.
Confusion between "which" and that." We use "that" to introduce restrictive clauses and "which" to introduce
nonrestrictive clauses. But most of us can't tell the two apart.