Opinion polls indicate that two thirds of Colombians would back a U.S. intervention to defeat the leftist rebel groups. The rebels now effectively control forty percent of the nations territory. Rumors have circulated for weeks that the U.S. was planning to send troops, but this is highly unlikely. At least for the moment. July 19; FARC troops were observed pulling out of the 42,000 square kilometer demilitarized zone south of Bogota.