What actually changes when you switch to short form?
A full citation is self-sufficient. Someone reading that sentence alone, with no prior context, can walk to a library and find the source. For a case that means: case name, volume number, reporter abbreviation, first page, pincite, and a parenthetical with the deciding court (omitted when the reporter itself identifies the court) and the year, plus any required subsequent history. Example: *Miranda v. Arizona*, 384 U.S. 436, 444 (1966).
A short form is parasitic on the full citation. It drops everything the reader can recover by looking back a few lines: *Miranda*, 384 U.S. at 444. The volume and reporter stay because they are the address; the first page and the date parenthetical go because you already gave them. Note the mandatory 'at' before the pincite in a case short form — that is the single most common formatting error students make.
The tightest short form is *id.*, which means 'the immediately preceding authority.' *Id.* at 467 says: same case as the last cite, different page. *Id.* standing alone says: same case, same page.
When are you allowed to use a short form at all?
The threshold requirement is always the same: you must have cited the source in full earlier, and the reader must be able to find that full citation easily. Beyond that, the trigger differs depending on whether you are writing a law review footnote or a court document.
In law review footnotes, Rule 10.9 supplies a bright line for cases often called the five-footnote rule: you may use a case short form if the case has been cited — in full or in short form, including by *id.* — in the same footnote or in one of the five preceding footnotes. If the last reference was six or more footnotes back, cite in full again. Journals police this on cite-check, and it is a routine source of edits on a write-on competition.
In court documents and memos, the Bluepages (B10.2) use a functional standard rather than a numerical one: use a short form if it will be clear to the reader, the full citation appears in the same general discussion, and the reader will have no trouble locating the full cite. In practice that means you should re-cite in full when you cross a major heading, start a new argument section, or the source has gone quiet for several pages. Also check local rules — some courts and many judges' chambers preferences require a full citation the first time an authority appears in each major section.
How does id. work, and when does it break?
*Id.* is italicized, including the period, and capitalized when it begins a citation sentence. It always refers to the immediately preceding authority in your document — not the last one you were thinking about. Never write 'Ibid.'; that is not Bluebook.
*Id.* breaks in a specific and predictable place: when the immediately preceding footnote or citation sentence contains more than one authority, you cannot use *id.* to point to just one of them. Fix it with a regular short form instead — *Miranda*, 384 U.S. at 444. The other trap is intervening text. If a full sentence of your own analysis, quoting or discussing a different source, sits between the two cites, the reader can lose the referent; when in doubt, use the named short form.
Also watch what *id.* carries with it. *Id.* imports the entire preceding citation, including any court-and-date parenthetical and any explanatory parenthetical you do not want repeated. And *id.* to a source with internal subdivisions requires you to update those subdivisions: *Id.* § 1983(b), not *Id.* alone, if you have moved to a different subsection.
What do short forms look like for each source type?
Short forms are source-specific. Memorize the four or five you will actually use.
For cases, use one distinctive party name plus the reporter and pincite. Choose the party that identifies the case in the reader's mind — *Brown*, not *Board of Education*; never 'United States' or a common party name alone, and never a generic government agency. If the case name is unmistakable from the immediately preceding text, Rule 10.9 permits dropping it entirely (384 U.S. at 444), but that is a stylistic option, not a default.
- Case: *Miranda v. Arizona*, 384 U.S. 436, 444 (1966) → *Miranda*, 384 U.S. at 444.
- Statute: 42 U.S.C. § 1983 (include the code edition year per Rule 12.3.2) → 42 U.S.C. § 1983, or simply § 1983 when only one statute is in play.
- Regulation: 17 C.F.R. § 240.10b-5 → § 240.10b-5.
- Book: Antonin Scalia & Bryan A. Garner, *Reading Law: The Interpretation of Legal Texts* 56 (2012) → Scalia & Garner, *supra* note 12, at 56.
- Article: Samuel D. Warren & Louis D. Brandeis, *The Right to Privacy*, 4 Harv. L. Rev. 193 (1890) → Warren & Brandeis, *supra* note 3, at 195.
- Constitution: no short form other than *id.* — cite it the same way every time.
When can you use supra, and when can't you?
*Supra* is a short form only for a limited set of sources — chiefly books, articles, reports, and other secondary materials, plus legislative hearings. Rule 4.2 bars it for cases, statutes, constitutions, regulations, most legislative materials, restatements, and model codes, because those all have their own dedicated short forms. Writing '*Miranda*, *supra* note 12, at 444' in a law review footnote will be redlined.
The format is author last name, *supra* note X, at page. The note number is the footnote where the full citation appears, and it is your job (or the journal's) to keep it accurate as footnotes shift. If a source has no author, use the title. If the natural short reference is awkward or two sources would collide, Rule 4.2(b) lets you define a shorthand with '[hereinafter Short Name]' in the full citation and then use that name in later *supra* forms.
Do not confuse this with Rule 3.5, which uses *supra* and *infra* to cross-reference parts of your own document ('see *supra* Part II.B'). Different rule, different function.
When must you go back to a full citation?
Re-cite in full when the five-footnote window has closed in a law review piece; when a brief moves into a new major argument section; when the same short name could plausibly refer to two different authorities you have cited; and when the source has not appeared for so long that a reader would have to hunt for it.
The controlling instinct is reader convenience, not rule compliance for its own sake. A judge reading page 22 of your brief should never have to flip back to page 4 to learn what *Miranda* is. When a short form would make a reader work, spend the extra line.
What errors actually cost you points?
Graders and cite-checkers see the same handful of mistakes. Omitting 'at' in a case short form. Using *id.* after a footnote containing a string cite. Failing to update the pincite in an *id.* so the citation silently points to the wrong page. Using *supra* for a case. Leaving a *supra* note number stale after inserting a new footnote. Italicizing the case name but not the period in *id.*
One more: short-forming a source you never cited in full. This happens when an early draft's full citation gets cut in revision. Before you submit, run a search for each short form and confirm a full citation precedes it.