First of all, the definition of great matters. How do you measure greatness? If being powerful is the most important measure of greatness, how can you achieve it? Through trade? Military campaigns? Exporting your culture like the US did on a big scale after WW2? Being a country where foreigners seek opportunities for success (and have a fair chance at achieving it) and thus being a country others want a good relation to? Is it to make your population wealthy? Being looked up to for advances in science and art? My post may seem to wander in all directions, but this is on purpose. It illustrates that "Make America Great Again" says shit all about what Trump actually wants to achieve, and how.