The Sahel was the last area in the northern parts of Africa, where vegetation can survive and where people were living at the time. Following the Sahel to the North one can find the Sahara desert which is a natural barrier that no invading force could trespass.
In the early 19th century, the ruling political party was the Democratic-Republicans. They selected their candidate through a vote of their members in Congress. This system let them control the White House for 20 years. Then the rivalry of John Quincy Adams and Andrew Jackson.divided the Democratic-Republicans into two after the 1824 elections and became Democrats and Whigs.
The answer is Presidential government, or a democracy.