What changed in the Bluebook's 22nd edition

Explanatory parentheticals are now required after see also, cf. and see generally (Rule 1.2); the 21st edition only encouraged them, so a bare citation after one of those signals is now an error. Some guides, including Georgetown's, require one after compare, contrast and but cf. too, so add one there as well: it is never wrong.

A new signal, contrast … with, introduces sources that differ in an important way, and compare … with now covers sources that are alike in one (Rule 1.2(b)).

Pin cites are required with every signal except see generally (Rule 1.2(f)). That puts in writing what was already expected rather than adding a new duty.

• See also Harlow v. Pemberton Props., 77 F.4th 512, 518 (8th Cir. 2023).See also Harlow v. Pemberton Props., 77 F.4th 512, 518 (8th Cir. 2023) (extending the repair duty to an oral tenancy).See also now takes an explanatory parenthetical. R 1.2
• See Halvorsen v. Treadwell, 71 F.4th 455 (2d Cir. 2023).See Halvorsen v. Treadwell, 71 F.4th 455, 461 (2d Cir. 2023).Every signal but see generally takes a pin cite. R 1.2(f)

In memos and briefs you may now drop internal quotation marks, brackets, ellipses, embedded citations and footnote numbers that are there only for readability, and flag all of those changes with one parenthetical: (citation modified) (Bluepages B5.3). The 22nd edition advises against the unofficial (cleaned up) and gives (citation modified) for the same job.

The rule permits rather than requires it: the usual parentheticals, such as (internal quotation marks omitted), still work, and a court's own rules control a filing. Guides differ on whether it belongs in law review footnotes.

• … 63 F.4th 220, 227 (7th Cir. 2023) (cleaned up).… 63 F.4th 220, 227 (7th Cir. 2023) (citation modified).(citation modified) is the 22nd edition's form for readability changes. B5.3

September is Sep., matching the three-letter months (table T12). The American Law Institute is A.L.I. in the date parenthetical of a model code or restatement (Rule 12.9.4).

A book with two or three authors now lists every author; et al. is for four or more (Rule 15.1). Lexis cases may use LX, as Westlaw cases use WL, and the older LEXIS form is still accepted (Rule 10.8.1).

• … 2024 WL 4410293, at *3 (E.D. Va. Sept. 27, 2024).… 2024 WL 4410293, at *3 (E.D. Va. Sep. 27, 2024).September is Sep. under the 22nd edition. T12
• Model Penal Code § 2.02(2)(d) (Am. L. Inst. 1962)Model Penal Code § 2.02(2)(d) (A.L.I. 1962)The American Law Institute is A.L.I. R 12.9.4

Rule 18 is reorganized for web-based sources, so rule numbers in older guides may point to the wrong place. Saving a copy of a cited web source is now required: add an archive link, such as Perma.cc, or keep a saved copy and say where it is on file (Rule 18.2.1(d)).

A new Rule 18.3 sets a form for citing generative AI output: save the output, then give who wrote the prompt, the model and its version, the prompt, the date and where the saved copy is kept. It covers AI output you choose to cite; it does not require you to disclose using AI.

Social media posts and messages get their own rule (Rule 18.10), and a new Rule 22 covers the law of Tribal Nations.