Why do the columns in the Old Supreme Court vestibule still stand?

The correct choice is based on the historical context of the Old Supreme Court vestibule and the significance of its architectural elements. The columns still standing serve as important artifacts of the building's original design and construction, which reflects the neoclassical style prevalent in the time they were built. This style was often selected to convey ideals of democracy and stability, key principles in the formation of the United States government.

Preservation efforts focus on maintaining the integrity of historical structures rather than altering them based on fictional narratives, such as fictional escape routes or resilience to disasters like fire. The columns are a testament to careful restoration and appreciation for historical architecture, aligning with the goal of historical preservation, which aims to maintain original features as closely as possible.

Understanding why the other options do not apply helps clarify the context: while the notion of fire-related reconstruction might seem plausible, the authentic architectural integrity of the columns plays a vital role in their preservation rather than needing to be rebuilt. Likewise, while the idea of them being part of an escape route sounds intriguing, it lacks historical documentation to support it. Overall, these columns represent a deliberate choice to uphold the historical significance and aesthetic vision of the building rather than being a mere functional aspect or a rebuilt feature.