It is really quite simple. The US relies on its Air Superiority. Special Forces Units act mainly as observers locating, identifying and assessing a target and its relative value. Info is then relayed back, where the information is further analyzed and augemented with ariel and satellite photographs and possibley electronic eavesdropping.
Then an Air Strike is planned and launched.
During the Vietnam War, a Marine Recon Group (code named Stingray) did something similar to the NVA. They acted as observers and would call in Air or Artillary Strikes.
The primary "mission" of such groups is to avoid detection and if detected to withdraw from the area, fighting only when it is absolutely necessary.
They are sometimes used in Raids, but their cheif value is to gather intelligence.