I think it was numbers and supplys
The supporters of Manifest Destiny believed that it was their destiny and right by God and history to expand
The Spanish establish colonies on the borderlands by building mission, presidios, and pueblos.Early in the 1500s, Spanish explorers reached Florida, but at first they did not build permanent settlements.Fearing that France might take over the area,Spain built a fort called St.Augustine in northern Florida.
The alliance system in Europe basically was if one country went to war, all of the other countries in that alliance would back up their buddy and go to war as well. This is what happened when Archduke Franz Ferdinand was assassinated and Austria-Hungary was arguing with Bosnia and each of their alliances go pulled in with them too.
