and still favor war or aggression against a defined evil such as Islamic jihadists...and in these here pages we done had some exchanges on the matter.
Of course, the answer is YES, Christians,
and nations who hold themselves ter be Christian in the most basic of terms, absolutely have an obligation to use force against them folks or nations that is hell bent on causing genocide,terror and mayhem against innocent peoples.

But the challenge is usually from folks on the liberal side of the aisle who ain't real fond of anything in the bible--unless they think it can be used against a conservative position. AN' thas the trouble--they think the bible says no war, no aggression, cause what they remember is "turn the other cheek".
Well, now, chillen's we does have ter turn the other cheek rather than give in ter a fight that is petty--a crude fella insults ya? Turn the other cheek. Brother-in-law stiffs ya' fer the dinner tab, turn the other cheek by paying the bill without makin' a big deal (but doan go out wif' him again lessen he has his wallet). In other words, try to keep peace even when the other person is rude, wrong, unfair etc. Cupiditas means personal interest, personal reference. Doan start no scuffle over small matters of cupiditas.
This doan apply ter deliberate attempts to destroy your city or nation, or your life. How do we know?
Romans 13:4: “For [the ruler] is God’s minister to you for good. But if you do evil, be afraid; for he does not bear the sword in vain. He is God’s minister, an avenger to execute wrath on him that does evil.” Mebbe this is easy ter understand when we think of Allies and Hitler.
Guess we can see that usin' armed force is justified in some cases. We need ter note, though, that it is limited to conditions fer the public good.
Sometimes what sticks in the craw of the liberals is that they wanna show how flawed the Allies is--as if whatever flaws one side has is an ipso facto obstacle to launching a fight against any other flawed regime or dictator.
But thas' jes' silly. Imagine a playground bully that beats the stuffin' outa every kid on the block. When a brave young'un finally stands up to the bully and tells her that he's a gonna bloody her
His tardiness doan equal her bullying--there is a thang called proportionality.
In Christian terms we's all--yep, ALL--imperfect, all sinners, all short of what God meant us to be. But not equally so. Some is jes' plain tryin' harder, despite a few slip-ups. Others ain't tryin', and in fact is tryin' not ter try! To be evil, in truth. When we lay it out , proportion makes a big difference. Some is a little bit bad, and sad about it, some is bad in a big, big way--on purpose.
So, see? Ain't no need to claim a small flaw is equal to a big flaw--that is an unjust claim. If we waited til we's perfect, nuthin' would ever be done.
Nope--a nation doan have ter be perfect to wage a just war against a bully. Bellum (Aggression, armed force) is justified when it is for broad humanitarian purposes. (I ain't named Aunty Belle --antebellum--fer nuthin' ya know?). When a sovereign deems his nation/ community is under attack and must be defended--even "taking the war to the aggressor" --this is a just cause for the benefit of the whole.
St. Augustine laid it out fer us: “We do not seek peace in order to be at war, but we go to war that we may have peace.”