I hate the arguement regarding checking a persons legal status. With the technology we have today it would be very easy. In fact it can be done at the private sector level. If you bounce a check to the grocery store it is known thoughtout the country within a day. Certainly if we wanted to get serious about this we could.
I think it is a completely bogus arguement. I think you're right, we only need the will to do it. I think that is the primary thing missing in all aspects of the border/alien/immigration issues. The will to do what needs to be done. I don't see any of it as particularly complicated as so many contend.
Control the border.
Enforce the law on illegals and employers alike.
Fund ICE so that it can properly process permits/visas/etc and monitor foreign nationals.