A wise website that dispenses free legal advice once said, "Good fences do not always make good neighbors." And we couldn't agree more.
In fact, fences, property lines, and trees are among the most common issues brought before Idaho court judges. Because of this, Idaho has an expansive section of code that specifically addresses what's known as a "spite fence."
If adjoining proprietors cannot agree as to the proportion or the particular part of a division fence to be made, maintained or kept in repair by each respectively, either party may apply, on five (5) days' notice, to a magistrate judge, for the appointment of three (3) viewers, who may examine witnesses on oath, and view the premises [...]. -Idaho State Legislature, 35-106
According to Jerry, a car insurance company with a yin for obscure laws and quirky national studies, Idaho code 35-106 means "the law prohibits 'mak[ing] malicious use of your property' just to disturb or get even with a disagreeable neighbor."
In short, you can't put a fence up, or any other structure for the matter, just to pi*s off your neighbor.
Any fence a neighbor erects needs to serve an obvious, functional purpose. If it doesn't, you can request injunctive relief or damages from a court to compensate you for your compromised views and the inability to enjoy your property.
But, there's a catch. The burden of proof falls on you to convince a court that your neighbor did, in fact, build the fence out of malice. In a scenario such a this, judges rely on photographic evidence, diagrams, or something that speaks to a purposeful ill will.
For more information how to handle a spite fence or structure on your property, click here.