What's the most defining part of American history?

[Blue3]

We've come a long way since the Declaration of Independence was signed, and the war for independence won. We started out as an alliance of British colonies, mostly composed of farmers, led by wealthy white male landowners who were contradictorily liberal idealists. Now we have a much more centralized government, more equality among citizens, and we're the world's #1 superpower.

What's the most defining part of American history?

[Blue3]

The early republic, Washington through Monroe made us who we are. Post WW2 era Truman through Kennedy might be the most "defining" part of American history.

Those aren't events.

For the first span of time you listed, the most notable events are the Louisiana Purchase (part of Westward Expansion), War of 1812 (attempted expansion which ended up not changing the status quo), and some Indian Wars.

The second span of time you mention is marked by the end of WWII, the Cold War, the Space Race, and the Civil Rights movement.

So which of these is the most defining part of American history to you?

[Blue3]

If you were to ask what the most defining part of a Person's lifetime was, hardly anyone would say their day of birth. It's not birth/creation that DEFINES you. It's what comes afterward, what you do with your life, that counts. It's not really American History until after it's begun, not its creation.

But if you must vote for that, the Revolutionary War and the forming of the Constitution happened during the Confederation period.

And the Gilded Age was defined by the events of the Robber Barons creating and growing their companies, industrially developing the country, and getting their way with a laissez-faire government. The Progressive Age was defined by events like the rise of the early labor movements, its specific struggles and victories.