Read the following excerpt from Federalist #14 by James Madison
Had overy State a right to regulate the value of its coin,
there might be as many different currencies as States, and
thus the (trade) among them would be impeded;
(unexpected changes) in its value might be made, and thus
the citizens of other States be injured, and animosities be
kindled among the States themselves. The subjects of
foreign powers might suffer from the same cause, and
hence the Union be discredited and embroiled by the
indiscretion of a single member.
According to Madison, ratifying the Constitution would
Improve the economy by
O allowing each state to have its own currency and trade
laws.
preventing trade by individual states with other
countries,
allowing only gold to be used as currency for trade
purposes.
preventing individual states from having their own
currencies.