In which time period were the political leaders' drawn from the nation as a whole, and had a smaller cultural and ethnic divide between the wealthy and poor? A

In which time period were the political leaders' drawn from the nation as a whole, and had a smaller cultural and ethnic divide between the wealthy and poor? According to wikipedia, 60% of the African-American senators EVER have been elected in the past 20 years. 40% of the total in the past 10 years. A significant proportion of the total African-Americans to have been in the house of reps are currently serving. Similar statistics for Latinos and Asian-Americans. Most western nations came from the British system, which literally had people born as noble.