Why were the Iroquois an important tribe for the U.S.?

The Iroquois were not really a tribe but a confederacy of five tribes [ a sixth tribe joined later].   These five tribes lived in the Eastern Woodlands, around New York.   Because these tribes were united, they could be a formidable [strong] enemy or friend.   In the French and Indian War, the Iroquois Confederacy were important allies for us [the English colonists].   The Iroquois helped us defeat the French in a war that ended up giving us all the land east of the Mississippi River.

But it was really the way these tribes were able to get along and the way they set up their government that had the most impact on us.   Important colonists like Ben Franklin, admired  the Iroquois Confederacy.   Each tribe ran its own affairs, but they met together to settle arguments between tribes and to fight against any enemy.   This is what a confederacy is all about.   Franklin thought that the thirteen English colonists should have a confederacy, just like the Iroquois.   Franklin also admired the way the Iroquois ran their meetings - it was totally democratic - anyone was allowed to speak.   Our first form of government was a confederacy too.  

When we united as one country and wrote the Constitution, we borrowed ideas from the Iroquois again.   The Preamble to the Constitution - "We the people of the United States, in order to form a more perfect union, establish justice, insure domestic tranquility ..." - was written just like the pledge that had united the five tribes of the Iroquois Confederacy.   Seen below is the flag of the Iroquois.  The design is based on the Hiawatha belt that symbolically shows the 5 tribe unity.  [from www.tmealf.com]  [image above from glenview34.org]