The Northwest Ordinance encoded values before settlement began

McCullough emphasizes that the territory later settled at Marietta was governed from the outset by the Northwest Ordinance, a piece of federal legislation that explicitly banned slavery in the territory and guaranteed support for public education. Critically, these commitments were established as governing framework before large-scale settlement occurred, rather than emerging organically or being fought for after the fact by settlers already established there.

His point is that this sequencing mattered enormously: institutions and norms are far easier to establish in a place before competing customs take root than to retrofit afterward, once economic and social patterns are entrenched. The settlers who arrived at Marietta were self-selected, at least in part, by these pre-existing values, since prospective colonists aware of the ordinance's terms could choose to settle there specifically because of them.

This illustrates a broader historical principle McCullough returns to: legal frameworks set early in a territory's development can shape its long-term character far beyond what might be predicted from the settlers' individual backgrounds alone.

Takeaway: the earliest governing rules established for a new community often outlast and out-shape whatever individual intentions its first residents brought with them.