Here's one in particular that I wish our current political "leadership" (and some of the recent past ones as well) would have learned. The quote (with my emphasis):
As a very important source of strength and security, cherish public credit. One method of preserving it is, to use it as sparingly as possible; avoiding occasions of expense by cultivating peace, but remembering also that timely disbursements to prepare for danger frequently prevent much greater disbursements to repel it; avoiding likewise the accumulation of debt, not only by shunning occasions of expense, but by vigorous exertions in time of peace to discharge the debts, which unavoidable wars may have occasioned, not ungenerously throwing upon posterity the burden, which we ourselves ought to bear.
The source of this apparently long forgotten wisdom?
The Farewell Address of President George Washington.
