Nixon stepped down in 1974, halfway through his second term, rather than face impeachment over his efforts to cover up illegal activities by members of his administration in the Watergate scandal.
It refers to the period of time between the fall of the Roman Empire and the beginning of the Italian Renaissance and the age of Discovery.
Conflict between other countries that are Russian allies always causes concern for war-weary americans because if the conflict continues, our government will be obligated to get involved.