In other words, we have a mess....
...(again)
We've always "had a mess" with the interplay of federal law and state law, and that is probably gonna continue for a while.
The real root of the issue lies in the Constitution, and in efforts of the federal government to broaden their level of control, and to bring standardization of the laws to the states.
A central theme of the Constitution is that the states are the primary authorities to define the laws that apply to their populations. The federal government's role in lawmaking is limited to those areas where the Constitution assigns a federal responsibility.
One drawback of that approach is that you can have 50 different ways of performing the same criminal justice task. You can also have very common criminal justice terms, like "Conviction" and "Indictment" mean 50 different things. A California "Indictment" is very different from a federal "Indictment" as we discussed above.
California and many other states have opted to relieve youthful offenders of the stigma of a "conviction" (with the exception of WIC 707 cases in California). But when Congress creates a federal statute, it's really necessary for them to do so using language that is consistent with the language of corresponding statutes of each state, or to write the federal statute so that it supersedes the state statutes.
Early in my career, I was given my first management job. The County's Housing Authority Police Department was disbanded following a number of internal issues and the County contracted with the Sheriff's Department to serve as the Housing Authority Police. I was assigned to run the operation. One of the strategies of keeping criminal elements out of the projects was to screen applicants for housing. The federal law expressly
required law enforcement agencies serving federally funded housing authorities (which we were) to perform criminal history background checks on applicants. California state law expressly
prohibited agencies from performing such checks. There had been a U.S. Supreme Court decision (Printz v U.S.) that would have allowed us to challenge the federal law, but it was in our interests to follow the federal law. I approached the County Counsel with the issue expecting a clear answer (remember, I was the "new guy" at this time). By the time that the issue finally got resolved, it took the efforts of several different folks to run bill through the California Legislature to permit such checks to be performed.