This is an interesting question.
Most likely the first instance of the idea of spaghetti comes from the Romans. In the first century B.C., the Roman poet, Horace, wrote of lagana, which were sheets of dough and they were most likely fried. As we study Roman foods more, we see other writers confirming the use of dough among the Romans. In light of this, we can say that concept of pasta came from the Romans.
With this stated, other nations also ate pasta, especially dried pasta, for long journeys. We know that the people of North Africa did this. This tradition continued in other explorations, which included the new world explorations. In light of this, we can say that pasta and spaghetti came to the Americas through European explorers. Eventually as the colonies spread, it came to South Carolina and the rest of America.