Because of lack of details, we must speculate on when that might be:
- Was it pre-Civil War America, when slavery was legal in the United States? Is that what we have to bring back in order to re-achieve greatness? Or,
- Was it post Civil War when the South was building out from under the destruction of its infrastructure? Was that the time of American greatness? Shall the South be repressed again? Or,
- Was it pre-World War I America when we built the Panama Canal and the great Teddy Roosevelt broke up the monopolies and the trusts? Should we take back the Canal and break up all the monopolist corporations? Or
- Was it during WWI when we instituted a draft and named a French General as CinC of our troops? Should we bring back the draft and put NATO under French control? Or,
- Perhaps it was WW II, when, facing a common enemy, we had rationing, and wage and price controls. Will Trump choose this period as our model for greatness. Or,
- Will Trump choose to model his administration after the era of Dwight Eisenhower, when we built the Interstate System, investing in infrastructure and charging a marginal tax rate of 91%?
Since I doubt that the Donald will ever deign to tell us before hand, so as not to dampen the surprize, I guess, I suppose we'll just have to see what he has decided was our greatest era.