...its how you got in. All of those processes are well defined.
And your alternative means that all people would have to register for work...lets see anyone pass something like that (national/state/county id card). Wouldn't float.
And why should AZ and other border states have to fund all of the expense to police people that shouldn't be here in the first place? Thats the basis of what they are saying. Fed inaction has created an unsustainable situation in their state, which they are now acting to correct.