In the case of Petit v. Minnesota, 1899, the U.S Supreme Court ruled on a dispute involving land ownership. The plaintiff, Petit, claimed that he had purchased certain lands in Minnesota from the railroad company which were granted to it by an Act of Congress in 1864. However, these lands were also part of those offered for sale to settlers under preemption laws by another Act of Congress passed earlier in 1857. The defendant was one such settler who bought and settled on this disputed land before Petit's purchase from the railroad company. The court held that although both Acts are valid and have their own purposes; when they conflict with each other as seen here - where same parcel is involved - priority should be given to actual settlers under preemption rights over subsequent grants made to corporations like railroads unless explicitly stated otherwise by Congress. Therefore, even though Petit legally acquired his title from a federal grantee (railroad), it could not supersede prior vested rights obtained through settlement and improvements made by actual occupants like defendant under preemption laws. Thus ruling favored Minnesota (defendant) affirming its superior right over disputed property against Petit's claim.

The dissenting opinion in the Petit v. Minnesota case argued that the state law, which allowed a second trial for defendants acquitted of murder due to insanity, violated the Double Jeopardy Clause of the Fifth Amendment. The justice contended that an acquittal on any ground is final and prevents further prosecution for the same offense. He disagreed with majority's interpretation of "acquittal," arguing it should be understood as a legal resolution in favor of defendant rather than merely factual determination about guilt or innocence. Furthermore, he expressed concern over potential abuses by prosecutors who could use this loophole to retry defendants until they achieve desired verdicts - thus undermining fairness and integrity within judicial system.