[TexasAg1996]

But, what does it mean that you can't apparate in and out of Hogwarts? Hmmm???

Securing your own home or a building is easy. You can't possibly secure a country. You couldn't, for example, build a fence on your southern border to keep out illegals. It's just not magically possible!

[TalonDJ]

You can't possibly secure a country.
Nonsense! We just have to enforce existing laws! And use Veritaserum on employers suspected of hiring illegals.