I just finished reading The Tuloriad last night, by John Ringo and Tom Kratman, and for the first time I find myself having to fervently disagree with the authors. I believe they made a serious mistake in the ending of the book, which they then compounded in the afterword.
First of all, let's start with a capsule summary of the afterword. Ringo and Kratman discuss the Battle of Lepanto, present their conclusion as "Bring a gun to a gunfight; bring a religion to a religious war", assert that the Christian fleet decisively defeated a numerically slightly superior Ottoman Turkish fleet because the Christians were driven by faith, and conclude on the strength of this argument that religious faith is a good thing and atheism is bad.
To start with, this argument is flawed because it assumes that the Christian fleet was driven and held together by faith, while failing to explain why the Ottoman Turkish fleet — overwhelmingly Muslims — was not. It's also flawed because it ignores that although the Turkish fleet outnumbered the Christians by about 7 to 6, not a very significant disparity in numbers to begin with, the Turkish ships were on average somewhat smaller, thus making the forces much more even than the huge disparity the authors suggest. It completely ignores any issues of the tactical situation, or of the quality of leadership on either side; and it completely ignores both that the Turkish galleys were largely crewed by slaves who probably were not highly motivated to fight hard for their enslavers, and that the Christian side had the Turks outgunned by roughly 2:1 in artillery (not to mention the Turks having inadequate ammunition for their cannon).¹ And as if that wasn't enough, it totally handwaves the question of whether a religious war is ever a good idea in the first place.
Which brings me to the end of the book, and the moment in which the Posleen clan chief Tulo'stenaloor tells the Jesuit Father Dwyer, "You have won; I will order my people to convert to Catholicism."
There are two things terribly, terribly wrong with this.
The first is that Dwyer should have replied (but did not), "No; we have not won, because there was no war between us to win. We came here to offer you our faiths, not to force one upon you." It's stated over and over again throughout the book that theirs is a mission of peace.
(Actually, although the stated mission was to offer many of Earth's faiths in the hope of finding one to fit the Posleen, only Catholicism was given any serious chance to speak; Islam was deliberately allowed to present itself only weakly, mainly to allow the token imam to lament the need of Islam to "keep its lunatics under control", and none of the other faiths ostensibly represented in the delegation even really got a look in besides it being mentioned once or twice that they existed. In practice, Islam was there to make Catholicism look rational by comparison, while the rest barely got even lip service.)
The second is more fundamental (and again, Dwyer should have pointed it out, but didn't). If you think that you can ORDER a people, even your own, to adopt a specific faith, and you think that doing so means one damned thing in spiritual terms and makes you any better than any other theocrat in history who has told a people "Convert or else", YOU'RE DOING IT² WRONG.
 The Battle of Lepanto really wasn't a case of the Muslims failing to bring a religion to a religious war. It was a case of the Turks failing to bring nearly enough naval artillery to a naval artillery battle, and bringing archers to fight musketeers and arquebusiers.
 Faith, that is.