Final answer:
Persons can't be legally held in a holding cell without charges or a court appearance due to the right of habeas corpus, and holding someone without basic sanitary amenities like a toilet or sink is generally seen as inhumane. The duration one can be held in such conditions is constrained by law and human rights standards.
Step-by-step explanation:
The question of how long someone can be held in a holding cell without a toilet or sink involves the intersection of human rights and legal standards. The expectation is that basic sanitary facilities should be provided to detainees. Writ of habeas corpus ensures that a person cannot be held for an extended period without being charged and brought before a judge, which includes the right to be told why they are being held. Considering international human rights standards and domestic laws, holding someone without access to basic sanitation, like a toilet or sink, for any extended period could be seen as inhumane and potentially unlawful. Notably, during the war on terror, there were debates about the detention of terrorism suspects at Guantanamo Bay without formal charges or court appearances, argued by President George W. Bush. But, the lack of sanitary facilities in a holding cell on its own could not justify an indefinite detention without trial or due process.