DEFCON
The DEFCON scale is a way of assigning a numerical value to the readiness of the American military. Higher DEFCON values are used for lower levels of readiness (during more peaceful situations), while lower DEFCON values are used for higher levels of readiness (during tenser situations where the possibility of military action is more likely). A DEFCON level of 5 corresponds to ordinary peacetime, while a DEFCON level of 1 (which has never been reached) corresponds to the most dangerous situations, like thermonuclear war.
DEFCON 4 for heightened alertness. DEFCON 4 is the first level of readiness above the baseline value of DEFCON 5 and thus constitutes a fairly mild increase in readiness (though an increase from DEFCON 5 to DEFCON 4 is certainly significant). This DEFCON level signifies increased intelligence-gathering efforts and, sometimes, the heightening of national security measures. However, it is not usually an indication that the military (or the nation) are in imminent danger of attack.
- In the modern world, it is thought that DEFCON 4 is sometimes issued after minor to moderate terrorist attacks and politically-motivated killings, or after would-be plots are uncovered. Presumably, this is done in anticipation of further violence as an attempt to prepare for and prevent it.
BYOP and enjoy the hunt..