John Ringos 'Posleen' Series
A rather interesting sci-fi series where in Earth is approached by a galactic confederacy of pacifists and is asked to create and act as the confederacies army because the confederacy member species have absolutely no clue on how to commit violence and are deathly afraid of those that can. The only reason they asked Terrans to fight for them is that the Alien invaders that they fight (the Posleen) are five years from earths doorstep, so the Terrans pretty much don't have a choice.
Problems: a) We have to protect our world plus two others. Any military person can see the TO&E problems and chain of command issues that will result.
b) relative lack of manpower. We're only out numbed about a million to one by the posleen. And the posleen are nasty canniballistic Reptilian-Centuars with rail gun tech that would smoke an M-1 easily that come in 'human waves'
c) equipment production isn't as best as the confderation hasn't the first clue about Henry Ford-style industrial production. This causes supply problems.
d) the aliens we're working for don't really trust us. Or are really aren't that helpful.
e)Forget air support. Posleen weapons planes from the skies like flies
Given this sort of background, you'd expect the monkeys to be meat for the posleen, but we've a few things going for us.
A) the Average Posleen has the brains of a gnat and is realtively schtoopid. They have leaders who make themselves obvious on flying disks. Sniper bait anyone?
B) The Posleen have no concept of indirect fire support. This saves humanites hide more than once.
C) The Posleen aren't used to food that shoots back. making them inexperienced with a vicious enemy used to scortched earth tactics
A very good series, really. Ringo manages to make believable modern characters thrust into a sci-fi setting and dealing with all the fallout of a total war on earth an in space against an enemy that is utterly alien and implacable. Many hard decisions are made by Humanity so far in this series, so which might be discomforting to the readers. But all in all a very good series.
Books:
A Hymn Before Battle: Earth Makes Contact
Gust Front: The Invasion of Earth.
When The Devil Dances: the war grinds on on earth
Hell's Fair: Counter offensive by the heros, anda Cybertank named 'Bun-Bun'
Die Wacht Am Rhein: The Posleen invade Germany, and Germany raises a specter fromt he past to defend her