During the nineteenth century, Hawaii was a constitutional monarchy, internationally recognised as a sovereign nation, with the full apparatus of a functioning democracy: an executive, an elected legislature, and a judiciary. Because the Constitution of 1864 wasn’t abrogated with the consent of the legislature, because the Bayonet Constitution of 1887 was illegal, and because at the time of the overthrow in 1893, Queen Liliuokalani was extremely careful to never cede her nation’s sovereignty, there is a strong case to argue that, under international law, Hawaii is an occupied nation.
In 2000, the Permanent Court of Arbitration in The Hague heard a non-contentious case, Lance Paul Larsen v The Hawaiian Kingdom. In the body of the award handed down by the arbitrators, the sovereignty of Hawaii during the nineteenth century was acknowledged. Because of this award, representatives of the Hawaiian Kingdom submitted a complaint to the Security Council of the UN, which has accepted the complaint and will investigate it in due course.
Those interested in this subject can read more about it here.