Yes and no. There are (at least) two ways to effectively outlaw such browsers. One is penalties for the browser distributor. However, this really only applies t

Yes and no. There are (at least) two ways to effectively outlaw such browsers. One is penalties for the browser distributor. However, this really only applies to entities that are subject to US law. Of course the law could go one step further and try to go after ISPs for allowing access to download them, but that's already proved difficult in other arenas. The other way to limit access to such browsers is penalties for users of those browsers. But that feels even less likely. Even if such a law were on the books, how would it be enforced? Either someone would have to report someone using an "illegal" browser or perhaps some method of fingerprinting that is somehow tied back to the actual user. Both of these seem far-fetched to me. So perhaps such browsers would be outlawed, but I'm not sure it would practically do much.