Or is this just a Hollywood invention, like Tom Cruise’s heterosexuality*?
It’s apparently common (I’m speaking from a lack of information about Westerns, simply what “everyone knows”) for a lawman to grab some likely youngster and declare him deputized. Thereafter the young fellow can shoot at will with the full force of law. Should I believe it, or not?
*(Sorry, sorry I know, easy joke.)
As I understand it… a deputy is a sheriff’s assistant who has been appointed by the sheriff with his own powers and responsibilities to uphold the law. Whoever has appointed the sheriff might place some restrictions on when and how he can nominate deputies. It would make some sense to me that in a small frontier town, the power would be fairly liberal, considering the difficulty of summoning outside assistance.
The one key point, I think, would be that the new deputy should understand the responsibilities that come with the position.
Certainly it has probably been abused in westerns, particularly scenes where the sheriff deputizes at least half the grown, able-bodied men in the town to go out and settle the murderous bandits or whatever. 
By the way - I love your username Love Rhombus 
Thenk yew. On this day, however, it may make me sound greedy. I’d just as soon settle for a Love Triangle :D.
[hijack mode]
Actually, the triangle may be more greedy, compared to the way I usually think of a love rhombus. There are a lot of possible variants, but the classic one that shows up all the time in melodramas and soap operas seems to work out like this:
two girls: A and C. two guys: B and D. (Usually one pair is best friends and the other pair work together or something like that.)
Either: B and C are together, A and D are working, largely independent, to split B/C up and steal the person of the opposite sex.
Or: A/B, C/D are together, but B/C are struggling against an undeniable forbidden attraction to each other.
[/hijack mode]
True. If there was a catchy way to say just two points other than a line, I’d settle for that.
In my state, deputies are usually hired by a standard procedure with resumes and interviews, aaaaand it doesn’t hurt to be related to the sheriff. In Marion County (Indianapolis) some VIPs were appointed “honorary” deputies. The current sheriff ended that practice and revoked all honorary badges.
The “likely youngster” part is probably not true. But some of the officers in the state agency I work for are also deputized as US Marshalls, which expands their jurisdiction.
Okay, say I have a public job, with powers and duties. It might be Registrar of Deeds, it might be Sheriff, it might be U.S. Marshall, it might be Alaska Secretary of Cultural Affairs.
I have a budget and the power to hire staff to assist me in carrying out my duties. I can hire people to work for me, using my powers to do the duties of my job under my direction. They’re my agents, my deputies. If I’m the Registrar or the Alaska Secretary, I may name my chief assistant my Deputy Registrar or Deputy Secretary.
If I’m in law enforcement, my assistants are my Deputy Sheriffs, my Deputy Marshalls, etc.
And in emergency, if I’m the top law enforcement officer in an area, I can deputize at need – deputize 20 citizens to keep the peace and direct relief efforts in the face of the disaster that hit town, say.
So, did anyone else think the thread title was “How does one get deputzed”?
…Just me, then? Okay. Sorry.
Wow, it’s not just you. I read the thread title as “How does one get De-Baptized”?
When I was much younger I enforced parking laws in the city of Williamsport PA. I was deputized for this horrible job. The mayor swore me in. As far as I know I was not allowed to shoot someone, but they may have kept that part from me, as I would have likely done so on any given day.