California’s mess long predates GWB.
It looks unambiguous but like so many laws there are other laws that conflict with it. Specifically in this case asylum laws. It won’t take more than a day for the leftist lawyers and no borders folks to find a judge who will issue a nationwide injunction. In fact they will probably find several such district court judges in different circuits to issue injunctions each of which would have to be litigated up through the appelat courts and then onto the supreme court. Trump would likely win in the end but in the meantime we would have years of caravans heading this way. We are setting up for a constitutional crisis and grounds for impeachment.
It is obvious at this point that we have an out of control and partisan judiciary. This is the time to confront that problem and for the president to exercise his executive power and tell rebellious judges that there is a reason the founders didn’t actually give them any real power other than moral power which they have forfeited.