Case law on this is very clear.
Until you clear immigration you are NOT technically in the United States, and they can pretty much do as they want with you.
Even if you are a citizen.
I am a naturalized US Citizen.
Over the past two years, I have had to re-enter the US at LAX and ATL airports. In LA, I have had to scan finger print and they always take a photo using the new electronic passport control.
Screw the Snowflakes!!