I'm all for reducing or eliminating federal functions and transferring them to state or local governments. $4.5 billion is a lot of money. But what happens when a parent moves across state lines? It would seem like there is a federal role in locating out-of-state parents. Apparently a large portion of suuport is paid in the form of income witholding, whether from salaries or tax rebates. Again, I can see a federal role there. Still $4.5 billion seems like far too much money.
Parents living in different states was one of the excuses given by advocates of federal involvement. States don't take much interest in out of state cases because they have to split the federal funding bounty with the other state. Certainly, all that's needed is interstate cooperation and coordination. There is no inherently federal role. In fact, domestic relations is not on the federal government's allowed to do list in the Constitution at all. Back in the olden days, non-payment of child support in interstate cases was the leverage used by non-custodial parents when women decided to move with the children and their boyfriends without giving dad a forwarding address. But today, when dad's already signed up to pay through the system ..... there are a lot of fathers being forced to pay child support through the system who don't know where their children are, whether they're safe, or even whether they're alive.
A lot of child support is paid through wage withholding today simply because that's the mechanism the federal government wanted to use. It then goes to private collection agencies and through the government system. That's part of what costs you $4.5 billion a year. There are around 60,000 government employees, all sitting in government provided offices, with government provided computer equipment, networked to a $4 billion computer system that keeps track of intimate details of the lives of every American adult.
Not just divorced people. When payments are processed through a private agency, they keep around one third of what they collect. Stealing the baby's milk money. The "compliance rate" -- the percent of what is ordered that ends up being paid, is actually less than it was back in the days when payments were made primarily by one parent sending a check directly to the other.