A republic is a form of government in which the people have sovereignty or the final authority - the final say in all matters. The people are sovereign in a republic.
Also, a republic is one that is limited to a narrow territory; throughout the ages republics have existed, the vast majority of which were small in geographic territory.
Theorists may classify the US as a "large republic." It's large, but not a republic. In fact it is an empire at home and abroad.
The problem is not that Americans do not read the Constitution. The problem is that the moneyed interests and their lawyer friends have read the Constitution and have come to the conclusion that their delegated power is not strictly limited nor clearly defined.
The problem is that we are arguing in favor of a document which was the product of an illegitimate conception, a gross power-grab that took place 200 years ago by the moneyed and landed interests of the day.
The constitution was a compact, not a suicide pact. Secession is the only sincere alternative for change.