The Kennedy et al. v. United States case in 1923 revolved around the seizure of a boat, named "Lotus," by U.S. authorities for alleged violation of Prohibition laws. The owners, Kennedy and others, argued that since the vessel was British and on international waters at the time of seizure, it was not subject to U.S jurisdiction or its domestic laws such as Prohibition Act which banned alcohol production and sale within US territories during that period. However, the Supreme Court ruled against them stating that while generally a nation's legislation cannot extend beyond its own territory unless expressly stated otherwise; there are exceptions where acts done outside a jurisdiction can still be punishable under its law if they were intended to produce detrimental effects within it - this principle is known as 'objective territorial principle'. In this case, even though Lotus was on international waters when seized with liquor aboard destined for US shores; it fell under these exceptions because her actions were aimed at producing harmful effects (violating prohibition) inside American territory. Therefore despite being foreign-owned & located outside national boundaries at time of arrest; Lotus could still be subjected to enforcement action by American officials due their intentionality clause present in objective territoriality rule upheld by court ruling here.

The dissenting opinion in the case of Kennedy et al. v. United States argued that the majority's decision to uphold a conviction for conspiracy to commit espionage was flawed due to insufficient evidence and an overly broad interpretation of the Espionage Act. The dissenters contended that there was no clear proof showing that the defendants had conspired with intent to interfere with military operations or aid enemies during wartime, which is required under this law. They also expressed concern about potential infringement on First Amendment rights, as they believed some activities prosecuted could be seen as legitimate expressions of free speech rather than criminal acts. Furthermore, they criticized procedural aspects of how lower courts handled this case, including issues related to jury instructions and evidentiary rulings.