higher prices required the creation of new factories to provide jobs
Russia.
No. The Tropics is the area from the Tropic of Cancer to the Tropic of Capricorn. Europe is not in this area and neither is the continental US. However, the US as a whole is in the tropics, because Hawaii lies south of the Tropic of Cancer.
Roosevelt used the "big stick" because he believed he had it to use. The US had proved a few years before that its navy could stand up to Spain and that the army and marines could hold its own its own in small-scale land wars. He believed that the US should continues its policy established by the Monroe Doctrine decades before to protect American countries from foreign intervention or take-over. The problem in his day was more from economic threats from foreign countries trying to collect debts than from dreams of colonization, but Roosevelt saw a parallel.