Originally intended to encourage states to collect child support this law has morphed into a cash cow for states. The more they collect child support from dads, the more the state receives in federal matching funds.

This is why no reform will happen in CS, and why mom's are not held accountable for how the CS is spent.

Federally, Title IV-D is the part of the social security act establishing the National Child Support Program. Through it, the federal government provides an incentive by matching the amount each state collects in child support.

https://dailycaller.com/2018/04/09/state-child-support-laws-destroy-families/