Final answer:
The Greek Revival or Classical Revival architectural style was used in the 19th century America to symbolize democratic ideals and was prominent in government buildings such as the Capitol.
Step-by-step explanation:
The architectural style that was historically used to demonstrate a commitment to democracy is the Greek Revival or Classical Revival style. During the 19th century, the Greek Revival style became synonymous with democratic ideals in the United States, stemming from the country's admiration for ancient Greek democracy. This style was prominently used in government buildings like the Capitol, but also in state capitols, courthouses, and eventually in banks and homes. The use of this style conveyed messages of power, stability, and governance grounded in democratic principles. On the other hand, modern architecture, as seen in the works of Van der Rohe and other modernists, came to embody different values, often reflecting new societal norms.