First of all - fantastic post and insight.
I highly doubt, however, there would be any laws capping nursing pay. The backlash would be so severe and it would be perceived anti-American/competition.
That said, it's a crazy time.
It's actually already a thing in limited areas. Massachusetts and Minnesota cap pay in long term care, and Pennsylvania is working on the same thing. Texas banned residents from working in larger contracts.
If there is a movement to target travel nurse pay, it will be sold to the public as a cap on how much the nurse agencies make, not how much the nurses themselves make. Which is fair. The bill rate, which is the amount per hour that the hospital pays for a nurse, is generally far higher than what they pay us. Back when I worked travel in Florida several years ago, my blended pay rate per hour was $41. The agency got 55. Now the bill rate is around $180-200 to pay me 100-110. The agencies have gotten greedy, which might be familiar to all of you who hate CMGs. It will be easy enough to say to the public "these nasty evil agencies are stealing money from you and from the hardworking nurses, they need to be regulated!" The regulation will just tighten the purse strings hard enough that the travel money becomes much less worth it compared to the abuse you receive and people will return to staff positions.
It's also worth noting that the term "contract" is very deceptive. The agency or hospital can drop me like a hot potato tomorrow with my health insurance vanishing at the same time and it costs them nothing, which gives this job a certain lack of stability that makes it harder for people that have families. The complaints EM physicians have about the scheduling is echoed here too; I get a schedule handed to me a week in advance and if I don't like the days I'm assigned to, sucks to be me-- which works for someone with no children but somewhat less so for anyone who is trying to have a stable home life. There's a reason why I want out of this profession and even if these rates were magically available for the rest of my career I wouldn't be doing it.