A nation should require all of its students to study the same national curriculum until they enter college

The statement fails to acknowledge all the factors while recommending a national curriculum to all students until they enter college.
Main advantage of common curriculum is that it develops sense of unity, nationalism in all the students when they study same values, philosophies, culture and history. Consider Case of India, which is a multi lingual, multi ethnic, multi cultural nation where substantial part of curriculum is shared by all the states, albeit sometimes in regional languages. This has helped develop a strong sense of nationalism in one billion people from different backgrounds while keeping their regional identity intact.

Further a common curriculum provides, fair opportunities for college admission, to all students despite difference in their economical background. For example private schools charging exorbitant fees, offer tailored curriculum best suited for college application, to well off student, thus giving them undue edge over poorer sections of society.

But a common nationwide curriculum fails to accommodate various local problems that may be incomprehensible to students from other regions of that nation. For example, in a curriculum of a particular region, it may be required to emphasize more on regional history, geography, culture, weather etc. of that region, than a common nationwide take on those subjects.

Also the statement fails to consider case of special education. Talented student need special educational provision for development of their talent from young age. For example long hours of practice sessions required for excellence in sports or music may require customized selection of courses that may not fit well with the vision of common curriculum.

Thus a system, where a significant portion of a curriculum is common for all the students, while it also makes provision for inconsistencies like regional identity and talent development, is recommended.