The constitution protects everyone in the United states. The area before you walk in before going through customs doesn't count, although you do have some limit

The constitution protects everyone in the United states. The area before you walk in before going through customs doesn't count, although you do have some limited statutory protections. American citizens are protected because we must eventually be allowed into American territory at which point american law kicks in, but we are not guaranteed that our property can also come through the border. My advice is always the same -- don't pass through any international border with anything you'll be too sad about losing. Countries are weird