Which individual is known for his efforts to strengthen the nation and was a principal author of the Constitution?

The principal author of the Constitution who played a significant role in shaping its final form is Governor Morris. He is best known for his contributions during the Constitutional Convention of 1787, where he not only drafted large portions of the Constitution but also provided the inspirational preamble that begins with "We the People." Morris's vision helped articulate the principles of a strong federal government while also addressing concerns about representation and governance. His influence was pivotal in creating a document designed to unify the nation and providing a framework that balanced power among the various branches of government.

Other individuals listed, while important figures in their own right, did not have the same central role in drafting the Constitution or in reinforcing the national structure as Morris did.