What specific law in the Minnesota statutes imposes a duty to retreat
before defending one's person?
This is a long standing common law doctrine (i.e. a law established by binding precedents decided by appellate courts), which has guided the interpretation of the statutory codification in Minnesota of the right to self-defense. This is because the statutory codification of the right to self-defense in Minnesota was held by Minnesota appellate courts not to have been intended by Minnesota's legislature to abrogate the common law rules and case law which it codified. This decision was made because it followed one of the standard principles of statutory interpretation in common law jurisdictions like Minnesota.
One of the leading modern cases of the Minnesota Supreme Court addressing the issue states, in some of the pertinent parts:
Minnesota has recognized that a person who kills another in
self-defense must have attempted to retreat if reasonably possible.
See State v. Buchanan, 431 N.W.2d 542, 548 (Minn.1988); State v. Austin, 332 N.W.2d 21, 24 (Minn.1983). Appellant distinguishes his
claim, asserting that there is no duty to retreat before using deadly
force to prevent the commission of a felony in one's home. The state
argues that self-defense within the home *900 and defense of dwelling
are so similar that defense of dwelling must incorporate the
self-defense duty to retreat.
Although self-defense retreat requirements were debated in common law,
it was settled that there was no duty to retreat while in or defending
one's dwelling. Cf. 1 Wayne R. LaFave & Austin W. Scott, Jr.,
Substantive Criminal Law, § 5.9(b) (1986); Rollin M. Perkins,
Self-Defense Re-Examined, 1 UCLA L.Rev. 133, 150-53 (1953). The
special status of the home has persisted over time, obviating retreat
requirements for people engaging in self-defense within their homes. “
‘It is not now and never has been the law that a man assailed in his
own dwelling is bound to retreat. If assailed there, he may stand his
ground and resist the attack. He is under no duty to take to the
fields and the highways, a fugitive from his own home.’ ” Gainer v.
State, 40 Md.App. 382, 391 A.2d 856, 862 (1978) (quoting People v.
Tomlins, 213 N.Y. 240, 107 N.E. 496, 497-98 (1914)).
Minnesota has long adhered to the common law recognition of the home's
importance, holding that “the house has a peculiar immunity [in] that
it is sacred for the protection of [a person's] family.” State v.
Touri, 101 Minn. 370, 374, 112 N.W. 422, 424 (1907); see also State
v. Hare, 575 N.W.2d 828, 832 (Minn.1998) (citation omitted) (noting
that at common law “defense of the home [was] considered equivalent to
defense of life itself”). A resident has traditionally been empowered
to use force, even deadly force, when necessary to protect the home.
Hare, 575 N.W.2d at 832.
Minnesota's codifications of the common law defenses of dwelling and
self-defense state in pertinent part:
"[R]easonable force may be used upon or toward the person of another
without the other's consent when the following circumstances exist or
the actor reasonably believes them to exist:
(3) when used by any person in resisting or aiding another to resist
an offense against the person; or
(4) when used by any person in lawful possession of real or personal
property, or by another assisting the person in lawful possession, in
resisting a trespass upon or other unlawful interference with such
property."
Minn.Stat. § 609.06, subd. 1(3)-(4).
"The intentional taking of the life of another is not authorized by
section 609.06, except when necessary in resisting or preventing an
offense which the actor reasonably believes exposes the actor or
another to great bodily harm or death, or preventing the commission of
a felony in the actor's place of abode."
Minn.Stat. § 609.065.
Minnesota statutes have never addressed whether a duty to retreat
attaches to defense of dwelling or self-defense claims. However, early
Minnesota caselaw rejected a duty to retreat in cases of self-defense
occurring in one's home.
State v. Carothers, 594 N.W.2d 897, 899–900 (Minn. 1999) (holding that "A duty to retreat is incompatible with the right to prevent the commission of a felony within one's home.").
State v. Carothers remains good law in Minnesota. See, e.g., State v. Devens, 852 N.W.2d 255, 258 (Minn. 2014) (holding that the duty to retreat applies in a common area hallway of an apartment building); State v. Glowacki, 630 N.W.2d 392, 399 (Minn. 2001).
The lack of a duty to retreat in one's own home, which is the law in Minnesota, is sometimes called the "Castle Doctrine" (from the aphorism, "your home is your castle").
A statute that abrogates the common law duty to retreat outside one's home is commonly called a "Stand Your Ground" law. Minnesota does not have a "Stand Your Ground" law.