Another way to put it, regarding 
@Petrolicious88's final point, here's a scenario for you guys:
Let's assume that you are the 
Commander-in-Chief (CIC) of the Armed Forces of country/region A.
The following is what you do know from the very beginning:
1. 
Country/region B, which is a neighbour of your country/region, has 
1000 civilians. The bilateral relations between the two country/region has always been 
tense, and 
many people from both countries/regions are far from being fond of the opposing side.
2. One day, relations between country/region B and your country/region got so bad that your government decides to 
go to war against country/region B.
3. Your country/region has a 
much more powerful militarythan country/region B. This means your country/region would have 
absolute chances of victory against country/region B.
4. This presents you, as the CIC of the Armed Forces of your country/region with 2 distinct choices - Either you could go the 
gentle but slow method, in order to minimize collateral damage and loss of life, or you could go 
rough but swift method, in order to achieve a quick and decisive victory.
Then, let's assume that some military experts of your country/region conducted a rough study and concluded the following:
1. If you choose the 
rough but swift method, the war against country/region B 
could be won within 5-6 months.
2. If you choose the 
gentle but slow method, the war against country/region B 
could only be won within 2.5-3 years.
But then, those military experts followed up with another rough study and concluded the following:
1. If you choose the 
rough but swift method, it is estimated that a 
whooping 20 civilians of country/region B could
 become war fatalities every month during the war.
2. If you choose the gentle but slow method, it is estimated that a 
meager 5 civilians of country/region B could 
become war fatalities every month during the war.
Those military experts then presented their findings to you.
But then, a military advisor hurriedly came to you with this news report:
"In case of war being waged by country/region A against country/region B, then 
country/region C (which is a well known supporter and ally of country/region B) would 
provide material, financial and intelligence support for country/region B. If the war between country/region A and country/region B 
becomes worse, then country/region C would 
consider intervening on the side of country/region B and 
fight against country/region A in order to help defend country/region B."
You also know very well that the 
military power of 
country/region C is 
a (near) comparable peer to your country/region.
The military advisor then explained that in case country/region C decides to intervene in the war, it is estimated that the military of country/region C could be 
considerably mobilized and sent to war 
within 4-6 months, and also could be 
fully mobilized and sent to war
 within 1-1.5 years.
Last but not least, he estimated that in case country/region C 
decides to intervene, the war 
could potentially last for another 1-2 years than originally envisioned, albeit victory for your country/region can be guaranteed.
Therefore, as the CIC of the Armed Forces of country/region A, here a question for you: 
What method would you choice?
Please analyse diligently and think carefully.