Final answer:
The earlier in time rule in U.S. law is false; the Last-in-Time rule applies, meaning the most recent law supersedes the previous one. Sole executive agreements are not necessarily longer-lasting than treaties due to changes in administrations. Historical treaties have often had complex impacts on different groups.
Step-by-step explanation:
The statement 'When a Code provision and a provision under a treaty conflict, the one adopted earlier in time generally controls' is false. In the realm of U.S. law, when dealing with conflicts between domestic law and international treaties, the principle known as the 'Last-in-Time' rule is generally applied. This rule stipulates that if a federal law and a treaty conflict, whichever was enacted last will prevail over the earlier one.
Now, focusing on the nature of executive agreements compared to treaties, it's not necessarily accurate to say that a sole executive agreement is likely to last longer than a treaty. Executive agreements can be more fleeting and subject to change with new administrations than treaties, which have a more rigorous ratification process and are intended to be longer-standing commitments.
It's also important to clarify that historically specific documents have had varying impacts on foreign and domestic policies. For instance, the Treaties of Paris and other historical agreements have often overlooked certain groups such as the American Indians, and the outcomes have varied widely for different populations involved, including Loyalists post-war treaties.