Why did theodore roosevelt think merely the threat of force was sufficient to achieve his foreign policy goals? a. recent military successes had established the u. s.'s ability to back up its threats. b. president mckinley had not been able to use u. s. military force to annex colonies. c. the american public did not support using military force to attain foreign policy goals. d. roosevelt felt that engaging in peaceful negotiation was more effective than using force.