These systems have been sustained via legal and/or extralegal measures from the colonial period to today. What's clear is that they have been around since 1619 and they result in economic and social advantage for some while taking it away from others.
Ten Racially Based Systems that have reinforced racial inequality and promoted racism since 1619
1619 - 1856: Slavery included the legal imprisonment, torture, rape, killing, and forced labor of millions of people on the basis of their African origin. This system economically and socially benefitted whites to the detriment of blacks.
1800 - 1866: Black Codes were laws restricting African Americans' freedom primarily through vagrancy arrests, the penalty of which often included involuntary labor.
1865 - 1944: Convict Leasing – legal system of penal labor practiced in the Southern United States, beginning at the end of the American Civil War through WW II. Many historians consider the treatment “worse than slavery”. Usually included involuntary labor for others' economic benefit
1870s - 1950s: Share Cropping – legal practice where landowner allows a tenant to use the land in return for a majority share of the crops the tenant produced. Tenants were sometimes beaten and forbidden to leave the land
1880s - 1940s: Peonage – illegal system of involuntary servitude or neoslavery that was widely practiced in the south after the U.S. Civil War. Although illegal, it was wide spread and the perpetrators were rarely prosecuted. Southern states and private businesses boomed with this free labor. It is estimated that up to 40% of blacks in the South were in bondage due to peonage in the beginning of the 20th century. Owners of business used severe deprivation, beatings, whippings, and other abuses to "discipline" their workers. (source: Blackmon, Slavery by Another Name)
1870s - 1960s: Lynching – illegal practice of torturing and killing by extrajudicial mob action. Although illegal, the perpetrators were seldom prosecuted. Congress refused to pass anti-lynching legislation even when thousands of Blacks were being lynched.
1876 - 1965: Jim Crow Laws - laws mandating and enforcing racial segregation often through violent means resulting in loss of life and a lower quality of life
1970s - Present: Mass Incarceration – legal practice of stopping, frisking, and arresting African Americans disproportionately and sentencing them to incarceration for low level offenses. Growing numbers are being incarcerated in for-profit prisons and many for-profit companies benefit from the labor of inmates. Most arrest are for low level drug offenses. Even though Blacks are no more like to use drugs, they represent the overwhelming majority of stops and frisks.
? - Present: Modern-Day Lynchings - the killing of unarmed black and brown people by law enforcement and others who are protected by the law may be on the rise. Here is a database that lists some of the more recent cases - Fatal Encounters