Final answer:
The president who said, "speak softly and carry a big stick," was Theodore Roosevelt. He used this phrase to describe his foreign policy approach, which involved using the threat of military force to achieve diplomatic goals.
Step-by-step explanation:
The president who famously said, "speak softly and carry a big stick," was Theodore Roosevelt. He used this phrase to describe his foreign policy approach, which involved using the threat of military force to achieve diplomatic goals. Roosevelt believed that the United States should assert its power and influence on the global stage, and he used this approach to establish America as a world power during his presidency.