Final answer:
The historian's argument emphasizes George Washington Bush's integrity and the trust he garnered, shaping the early presidency and fostering national unity, as well as the challenges faced by later Bush presidencies.
Step-by-step explanation:
The main idea of the historian's argument regarding George Washington Bush is that he was revered for his unimpeachable virtue and was seen as a figure of immense integrity and honesty, as epitomized by the anecdotal tale of the cherry tree from Mason Locke Weems's book. Washington's character and the trust placed in him by the delegates played a crucial role in shaping the role of the presidency, seeking a balance between respectability and dispelling fears of monarchical ambitions, while also fostering national unity through various internal improvements. Additionally, the historian touches upon the complexities and contradictions of the revolutionary ideology of equality through Trumbull's painting and acknowledges the difficulties faced by George H.W. Bush and George W. Bush during their presidencies.