Image result for What were the US benefits of the Panama Canal
Because of the Canal, the U.S. was able to ship supplies so much faster. The faster a country can ship, the more willing they are to trade. They are willing to trade more because they don't have to spend so much money on fuel. Because they spend less money on fuel, they can carry more supplies.
To expand to new territories and to defend the kingdom. however he warns that its not enough having a strong army but to maintain morale among the troupes and citizens