Like most Repub ideas, it's an end around...

You can already "deal insurance across state lines." That's the start of the lie.

What they really want is to circumvent the state insurance commissions that regulate the insurance industry. That way, they can do the typical race to the bottom.

What they want is to force states into competition to relax their insurance regulations so that they can job shop to the state with the most lax rules and sell using those rules in all 50 states. Not a very "states rights" attitude, of course, but when did they ever let their own ideology stand in the way of profits?

So basically, if your state happens to have good consumer protections, Repubs want to be able to get around that.