Notice the peak year is 1990, Gun Control peaked in 1968 with the passage of the Gun Control Act of 1968. With that act, the Murder rate went UP. As Congress weakened that act in the 1980s, it lead to a DROP in murder after 1990. The effect of any law is often 5-10 years later, thus the 1968 Act full affect started around 1975-1980, the full effect of the drop in Gun Control in the early 1980s, came if effect with the drop in murder rate after 1990.
Side note: It has been extremely hard to get a hand gun permit in New York State since the Passage of the Sullivan Act in 1912 (a product of the New York State Legislature). Similar restrictions on owning pistols have been on the books in New York State since about the same time period. The vast majority of weapons used in crimes in New York, before and after the passage of the Federal Gun Control Act of 1968 has been illegal under New York State Law, and after 1968, illegal under Federal Law.
Now, before I go into an argument that Gun Control had no effect, the Studies I have read all pointed out the raise and drop in the murder rate do NOT correlate with increase (or decrease) Gun Control laws, increase prison sentences (or decrease prison sentences) etc. There is one report that shows a slight connection with Abortion, but it appears to be more coincidence then a real connection (restrictions on Abortions staring in the 1980s did NOT seem to have an affect on the murder rate).
The two trends that seems to have affect is the migration of African Americans to northern urban centers starting in the 1920s and increase spending on Children and Youth starting in the 1960s. These trends are 15-20 years trends but seems to be the answer.
Migration of African Americans from the Rural South to Urban Northern Cities.
The vast majority of African Americans lived in the rural South prior to WWII, they started to immigrant north during WWI, and this accelerated during and after WWII (For example Mississippi was Majority African American in the late 1880s till the 1930s, then became majority white). These African American lived in and were the product of the American South. Historically the American South had the highest Murder rate in the Country. In fact if you remove the South AND African Americans from the Murder counts, US Murder rate is lower then Europe's.
African Americans of the 1880-1940 period were a product of this Southern tradition of violence. This culture was a product of who settled the South (former Herders from Scotland, England and Ireland) whose traditions were never to take an insult without a response, to response to any perceived act of "disrespect" with violence and to seek violence revenge if someone did that person "harm" (including slights and other interactions that most people laugh off). This culture of violence started with who settled the South, but made worse by the introduction of Slavery, which required instantaneous violence to prevent any widespread slave revolt.
The post Civil War era did NOT see a reduction in violence (even when firearms were outlawed). African American were both victims of this culture AND part of that culture and thus absorbed those norms, as norms within the African American Community. The African Americans who moved North, starting during WWI, brought with them this culture of violence.
While I am concentrating on African Americans, you also see this in Southern Whites who moved North. Southern Whites had two advantages over African Americans, first, most of the Southern Whiles did NOT come from the deep South (As did most of the African Americans), but the more marginal areas of the south (such as Appalachian). In these marginal areas the Southern culture of violence was not as deep and thus easier for these Southern Whiles to adopt Northern Standards. The Second reason is Southern Whites were better able to mix with people already in the Northern Cities and thus were quicker able to absorb Northern Traditions (i.e. you had better mixing of Appalachian Hillbillies, with other foreign immigrants AND other whites from the rural areas of the North then between any of these three groups with African Americans).
This is complicated for statistics were race based NOT where the person who did the crime come from, thus a lot of ex-Southerns acts of violence was called "violence by whites" (and thus diluted by white population from other areas of the US and from overseas) while African American violence were recorded as being done by African Americans. Thus African Americans were shown to be violent, but the similar Violence of Southern Whites was diluted by the larger northern white and foreign white immigrants and they much lower rates of violence.
Most African Americans moved north After WWII, but they were of the age (Generally over 30) when they are settled and having a family takes them out of social groups that interact other then for work. On the other hand, they children, also a product of the South AND a product of the African American Community that was still dominated by people from the South, took with them into life of the inner city, this Southern, don't back down, fight for respect tradition. Thus you saw the increase in Murder Rates in Northern Inner Cities starting in the late 1950s, and accelerating in the 1960s.
Now, people absorb the dominated culture they are raised in. In the North it is a much less violent culture then the Rural South. Thus as African Americans became more and more removed from the Rural South, they replaced rural south traditions with Northern Traditions (i.e. Laugh off slight insults, work with each other, respect is internal, not what others think of you, but what you think of yourself). Along with these Northern Traditions is a tradition of NOT fighting over minor issues (and a tendency to view everything as minor). Starting in the 1980s you had mostly third generation of African Americans in Northern Cities (i.e. it was their Great Grand Parents who moved north, not their parents or grandparents). The Southern Tradition of fighting over Respect and one's "Manhood" became something of a distant memory, something to talk with relatives about long dead ancestors. This overall change in African American Culture lead to a less violence inner city and with a less violent inner city, less murder.
Children and Youth Spending
The other major influence was the increase funding for Children And Youth Services as part of Lyndon Johnson's Great Society program. In many abusive situations, the children learn to be abusive, as they see their fathers beat up their mothers and get away with it. These boys (it is mostly Males who are violent, the girls learn the lesson of being "helpless" and thus something to be beat on) will absorb the norms they see in their lives. Above I mentioned how African Americans absorb the norms of the Rural South, in abusive situations, these children absorb the norms in their own home and learn violence is the way to go. These same children slowly grow up and become violent in school and other social groups, and tend to be the people who are violent in their 20s and are the role models for their own children (and the cycle continues),
The increase spending on Children And Youth (and the related development of Protection from Abuse law) permitted Governmental units to intervene is such situations and correct the errors. The Children, seeing that they family were being "Punished" (Punished in the child's eyes as they see themselves removed from their parents and put with "strangers"
internalize that such violence is NOT good and make efforts to break the cycle, i.e. Males try NOT to abuse their wives/girlfriends and women learn it is NOT right to be a punching bag (I do a lot of PFA work and you be surprised how often you find an abusive husband/boyfriend with a submissive wife/girlfriend, they find each other). This change often takes generations to work its way out of the family (i.e. each generation gets better at NOT getting into the abuse cycle). A side affect of this is, each generation also learn Violence is NOT the answer to problems within. This is again compatible with the murder rate increase in the 1960s (as the Children and Youth became more aggressive) but the effect would NOT kick in for 20 or more years (1990 is 20 years AFTER 1970, most of the Great Society Programs kicked in from 1966-1970, thus the decline after 1990 fits the drop in murder rates after 1990.
Now, the above two reasons are NOT incompatible (i.e. BOTH could be working together), but I mention them for they provide a better explanation for the drop in the Murder rate then the various Gun Control laws passed since WWI (and the claim that Legalized Abortion is the reason, i.e. less unwanted children, mean more children that are loved as children and thus such children grow up to be less violent).
Edit history
= new reply since forum marked as read
