In the United states, how and when did child support come into law, and who lobbied for it? Was there any opposition? How was it enforced in its early days?
It's always been - in one form or another starting with our colonies using the English "poor laws" as a base (and later, "bastardy laws") which were to help communities get reimbursement from the relatives of the people they helped. The colonies each had their own laws or own interpretation of laws written in another colony. In the early 1800's came the laws for getting the father to support the child/ren instead of the communities and private charities. It became criminal in 11 states in the late 1800's, to not support your child/ren and the father could be publicly charged (don't jump on me - back then all the laws were written that way because there weren't any deadbeat mothers I guess). By the early 1900's 46 states had similar laws.
There was debtors prison (abolished in the 1800's) whipping and a fine for the father if there was a child born out of wedlock (also abolished in the late 1800's I think), and in the late 1800's/early 1900's there was prison and hard labor.
In 1950 Uniform Reciprocal Enforcement of Support Act (URESA) was enacted in all 50 states and in the early 1970's the ball really started to get rolling with new laws and amendments with things like wage garnishments, tax liens, etc.
So sorry for the delay!
http://www.child-support-laws-state-by-state.com/child-support.html
https://en.wikipedia.org/wiki/Child_support_in_the_United_States
http://singleparents.about.com/od/paternity/a/history-of-child-support.htm
http://scholarship.law.gwu.edu/cgi/viewcontent.cgi?article=1406&context=faculty_publications