The dollar under the gold standard, like any precious metal-based currency, is still a creature of the government and of politics (and therefore politicians). The government selects a unit of account and employs its military to levee taxes, which generate demand for the currency. Balance of payments generally requires that the government somehow spend the money it collects (else the economy is sucked dry) even under static conditions, but economic growth has always required expansion of the money supply. Thus for thousands of years politicians have been adulterating coin to promote growth.
During the Civil War or World War II, inflation was generated by fiscal policy on unprecedented scales - the federal government using the twin printing presses of the Treasury (Greenbacks and Securities) to purchase goods, in turn inducing those producers to produce more. In other words, if Lincoln printed a bunch of Greenbacks and as a result their value dropped, that value movement implies that those Greenbacks were actually willingly or not-so-willingly accepted in return for goods and services, which were themselves put to use winning the wars.