stylistic:tone
Statutory construction

There is a controversial legal maxim in American law that " Statutes in derogation of the common law ought to be narrowly construed ". Henry Campbell Black once wrote that the canon "no longer has any foundation in reason". It is generally associated with the Lochner era.

The presumption is that legislatures may take away common law rights, but modern jurisprudence will look for the statutory purpose or legislative intent and apply rules of statutory construction like the plain meaning rule to reach decisions. As the United States Supreme Court explained in United States v Texas, 507 U.S. 529 (1993):

Just as longstanding is the principle that "tatutes which invade the common law... are to be read with a presumption favoring the retention of long-established and familiar principles, except when a statutory purpose to the contrary is evident. Isbrandtsen Co. v. Johnson, 343 U.S. 779, 783 (1952); Astoria Federal Savings & Loan Assn. v. Solimino, 501 U.S. 104, 108 (1991). In such cases, Congress does not write upon a clean slate. Astoria, 501 U.S. at 108. In order to abrogate a common-law principle, the statute must "speak directly" to the question addressed by the common law. Mobil Oil Corp. v. Higginbotham, 436 U. S. 618, 625 (1978); Milwaukee v. Illinois, 451 U. S. 304, 315 (1981).

As another example, the Supreme Court of the United States in 1877, held that a Michigan statute that established rules for solemnization of marriages did not abolish pre-existing common-law marriage, because the statute did not affirmatively require statutory solemnization and was silent as to preexisting common law.

Court decisions that analyze, interpret and determine the fine boundaries and distinctions in law promulgated by other bodies are sometimes called "interstitial common law," which includes judicial interpretation of fundamental laws, such as the US Constitution, of legislative statutes, and of agency regulations, and the application of law to specific facts.