Cancel the air raid sirens, and come out of your fallout shelters. WWIII has not begun.
This morning, the U.S. military dropped a bomb containing ten and a half tons of explosives, the GBU-43, on the Nanaghar province in eastern Afghanistan. The GBU, dubbed the "Mother Of All Bombs," or MOAB, is the largest non-nuclear explosive device in the U.S. arsenal. It detonates in mid-air, relying on the shockwave to inflict massive damage on a targeted area below, particularly cave systems. This is the first time the weapon has been used in combat.
This strike was carried out in support of Afghani forces combating ISIS in the region. The target of the strike: an ISIS subterranean complex built in one of the many cave systems that run throughout the region.
This mission was reportedly the result of months of planning, with the bomb being brought in specifically for this mission. It was carried out under the order of Gen. John Nicholson, the commander of U.S. forces in Afghanistan. It was used in response to an intensification of conflict between Afghani forces and ISIS in the province. In a statement, Gen. Nicholson called the MOAB "the right munition to reduce these obstacles and maintain the momentum of our offensive against (the Islamic State)," in reference to the difficulty in engaging an enemy with few surface installations that would be vulnerable to traditional bombing. The military has also issued a statement, saying that "U.S. forces took every precaution to avoid civilian casualties with this strike."
To summarize: the U.S. has not attacked any sovereign nation in this move. The mission was carried out in support of an ally. The target was an installation of a militant terror group whose stated goal is the destruction of Western society and the return of their home region to the Dark Ages. While no casualty reports were available at the time of writing, unless ISIS was using human shields, which they have been known to do, civilian casualties were minimized, hopefully non-existent.
So no, we are not at war today anymore than we were yesterday. We have just upgraded from a weed-whacker to Roundup in the war against terrorist weeds.