The border is secure. (Only tiny numbers of criminals & terrorists still attempt to sneak in.)
Guestworkers will *leave* freely, it's not a life-or-death trial to return to work again.
Guestworkers will PAY TAXES.
Guestworkers will have reduced eligibility for benefits.
Guestworkers will be much harder to use to displace citizens from jobs.
Guestworkers who make it in this country doing menial work perhaps can eventually become citizens, and they are citizens we need.