What evidence is there that the nation's Founders
considered dissent very important

First Amendment and the belief in 'questioning authority'.

Explanation:

Dissent is an important mechanism of a democratic government. It gives the right to the citizens to reject or voice out any discontentment in the authority of the government.

Similarly, the founding fathers of the U.S Constitution has also incorporated certain values into the constitution that promotes dissent. Although no particular provision specifically protects dessent in the U. S Constitution, the First Amendment gives the right to the people to express their ideas and beliefs without unwarranted government prohibitions.

Founding fathers like Benjamin Franklin also quoted, “It is the first responsibility of every citizen to question authority.” which promotes the essence of dissent. Therefore, the presence of the First Amendment and founding father like Benjamin Franklin supporting 'questioning of authority' provides evidence that the nation's Founders considered dissent very important.