The heart of the argument—where the documentary record has the greatest claims to strength—concerns Indian influence on the joining together, first of the colonies under the Articles of Confederation, then of the states under the federal Constitution. Accordingly, the present essay focuses on these topics—that is to say, on the formation of the American union. It concentrates on the writings of Donald Grinde and Bruce Johansen, who have made the most detailed and authoritative statements of the Iroquois influence thesis. It summarizes their argument, examines the evidence, and concludes that their position is unfounded.

What is the author’s main argument in this passage?

Grinde and Johansen’s theory is mostly incorrect.
Grinde and Johansen’s theory is vague and unclear.
Grinde and Johansen’s theory is correct, but flawed.
Grinde and Johansen’s theory is correct without a doubt.