What does a "foreign enemy" have to do with presidential security in the homeland? Shawn Robert Adolf tried to hit BHO here in Denver. Oscar Ramiro Ortega-Hernandez fired shots at the Whitehouse with BHO. Aaron Snyder tried to hit Gov Ritter inside our State Capitol. Robert Pickett fired shots at GWB. Ronald Gene Barbour and  Francisco Martin Duran tried to hit Clinton. All of the above are US certified wack jobs. No foreign enemies needed.

To be fair there have been foreign plots but those were to hit presidents when they were on foreign travel. The USSS doesn't base security staffing on wether or not they like the person. They protect them all.