There is no such thing as a "necessary evil". If something is necessary it can't be evil, and if it is evil, it can't be necessary.
Try to find some other justification for the State and its enforcers and military, and "taxation", and "laws".
The above was posted on the spur of the moment as my Facebook status a couple of days ago. It attracted the attention of a government extremist. The thread is long, but you might enjoy seeing just how a statist attempts to justify their beliefs.
If you don't "do" Facebook, I understand, but you are missing some amusement. Someday, I may try to post the whole thing here, but probably not. It is long and still growing.
Here is the link; Link