Which President was in office during the establishment of the Papahanaumokuakea Marine National Monument?

The establishment of the Papahanaumokuākea Marine National Monument took place on June 15, 2006. This significant event was under the presidency of George W. Bush. The monument is noteworthy as it protects an expansive area of the Northwestern Hawaiian Islands, encompassing both cultural and natural resources, highlighting the importance of preserving marine environments.

George W. Bush's administration focused on conservation efforts, which led to the designation of Papahanaumokuākea as one of the largest marine protected areas in the world. This action was part of a broader strategy to preserve America’s natural heritage and address environmental concerns.

In contrast, the other options do not align with the date of the monument's establishment, as the actions leading to this significant conservation milestone did not occur during the tenures of George H.W. Bush, Bill Clinton, or Barack Obama regarding this specific marine protected area.