What slowed progress during the construction of the Panama Canal?

The construction of the Panama Canal faced significant challenges, notably due to diseases such as malaria and yellow fever, which heavily impacted the workforce. During the early stages of the project, a considerable number of workers fell ill or died from these diseases, leading to a slowdown in progress. The high mortality rates and illness not only reduced the available labor force but also instilled fear among workers and potential recruits, further complicating staffing the labor-intensive project.

Efforts to combat these diseases included measures such as draining standing water, improving sanitation, and utilizing mosquito control strategies, which ultimately helped to mitigate the health risks and allowed work on the canal to continue effectively. This focus on health and safety was a crucial factor in ensuring the eventual success of the canal's construction.

While other factors like political objections or Roosevelt's policies did play a role in the canal’s history, the direct impact of diseases on the workforce was a primary reason for the initial slow progress.