Read this passage from the u. s. constitution:

the congress, whenever two thirds of both houses shall deem it necessary, shall propose amendments to this constitution . . which . . shall be valid to all intents and purposes, as part of this constitution, when ratified by the legislatures of three fourths of the several states, or by conventions in three fourths thereof, as the one or the other mode of ratification may be proposed by the congress.

which statement best reflects the purpose of the passage?

Correct  

Further explanation:

Changing the Constitution of the United States is an intentionally difficult process in which an amendment must be proposed and approved by 2/3 of Congress or 2/3 of the state legislatures before being ratified by 3/4 of the States.  Normal bills passed by Congress become law with the signature of the President.  Amendments to the Constitution, however, require a more stringent process, as described in the passage quoted from the Constitution.

the quote by walter cronkite contributes to the central idea of the text by supporting the central idea. cronkite argues that what is deemed “right” for and in america may not be good for other countries. this supports the central idea of the text, that the vietnam war was unpopular in america for multiple reasons- including cronkite’s.