A copyright infringement case is built on two showings that map neatly onto the statute: ownership of a valid copyright, and copying of protected expression. Ownership requires the work to be original and fixed in a tangible medium, and while registration is not required to create the copyright itself, it is a jurisdictional prerequisite to filing suit and the gateway to the remedies that make litigation worthwhile -- registering before infringement begins, or within the statute's grace period, unlocks statutory damages and attorney's fees that let a plaintiff avoid proving actual harm at all. Copying is rarely provable by direct evidence, so courts infer it from two elements: the defendant had access to the work, and the two works are substantially similar in their protected expression, with the similarity threshold dropping as the evidence of access strengthens, until at the extreme a work so strikingly similar that independent creation is implausible can substitute for proof of access entirely. Only protected expression counts -- ideas, facts, methods, and short phrases are excluded no matter how closely they are echoed.

Fair use is where most contested copyright cases are actually won or lost, and it is decided under a four-factor balancing test rather than a bright-line rule: the purpose and character of the use, including whether it is transformative or commercial; the nature of the copyrighted work; the amount and substantiality of the portion used; and the effect on the market for the original. Because no single factor is dispositive, fair use outcomes are notoriously hard to predict from the pleadings alone, which keeps summary judgment contestable well into the case. Statutory damages add their own strategic layer, ranging from $750 to $30,000 per infringed work at the court's discretion, climbing to $150,000 for willful infringement or dropping to $200 for innocent infringement, and a plaintiff with multiple registered works can elect statutory damages per work rather than proving actual damages and the infringer's profits. Online platforms add a further wrinkle through the DMCA's notice-and-takedown safe harbor, which can shield a host from monetary liability entirely if it responds properly to takedown notices.

Fair use is where most contested copyright cases are actually decided, and because its four factors are balanced rather than ranked, the outcome often stays genuinely uncertain past summary judgment, which keeps settlement leverage roughly bilateral for longer than in most IP disputes. Registration timing is a separate lever entirely: a plaintiff who registered before the infringement began can elect statutory damages per work and recover attorney's fees without ever proving actual harm, while a late registrant is limited to actual damages and the infringer's profits, a much harder number to establish. Willfulness pushes statutory damages toward the $150,000 ceiling and injunctive relief remains available regardless of the damages theory, so an ongoing infringement often settles around the cost of stopping it rather than around the historical harm.