So the question was raised on the NoR, "what is the role of the mortar in infantry combat"?
Very simply, mortars are an indispensible tool for heavy infantry.
When I say indispensible I don’t mean “useful” or “a good thing”, I mean indispensible, as in you don't do without them if you can avoid it.
One of the missions of heavy infantry is to operate and complete objectives without extensive support from external and supporting forces in areas ahead of the main secured areas.
To accomplish this mission, heavy infantry need to be able to move rapidly through varied terrain and facing varied and potentially semi-hardened resistance. Additionally they may face organized lines of resistance, in which salients and breakthroughs must be created and exploited. To do this, the order and discipline of opposing forces must be disrupted at key points.
Finally, supporting functions such as battlefield illumination, terrain marking, and potentially mine clearance are critical.
All of these functions are supported by light and medium mortars (as well as medium and heavy machine guns), which should ALWAYS accompany heavy infantry maneuver elements. They are not themselves maneuver elements, but fire support organic to those elements.
Heavy mortars are for FOB/FOP and FFP/FFB; as a semi fixed emplacement. They are also useful in vehicle mounts if such mounts are supported for that mortar platform. In this role their primary function is perimiter defense.
Now as relates to the U.S.; we currently don’t have traditional heavy infantry as such.
Or rather we have medium/heavy infantry, but we use them tactically as medium infantry. We don’t include many man portable crew served weapons with them but they are otherwise equipped as heavy infantry and/or mechanized infantry.
In fact, we are heading more and more towards a full heavy infantry load for every soldier; whether they are employed as heavy infantry or not. This is a natural outgrowth of our increasing reliance on technology; and our force protection philosophy.
We don’t really have traditional light infantry anymore either. Up until recently we HAD regular organized light infantry, but have mostly disestablished them; except in the person of the Rangers, MEF, and SOCOM forces.
This suits our current rapid fire/rapid maneuver style of warfare, which counts on extensive supporting elements, and combined operations elements. In this we are able to effectively leverage our HUGE C3I advantages.
Of course this leaves the mortars role as somewhat ill defined. It is still extremely useful, but the clear tactical doctrine for it’s use is kind of out the window.
The mortar is currently used by U.S. forces as an "as needed weapon", primarily for building clearance and tactical illumination. It can also serve as a company commanders personal artillery, much as the MLRS functions for a brigade or division commander.
