Final answer:
The U.S. often plays a significant role in international disaster relief, but it is not always the leading nation. President George W. Bush's foreign policy is more associated with neoconservatism than liberal internationalism.
Step-by-step explanation:
The question regarding whether the United States typically has a leadership role in major international disasters can be answered as somewhat subjective, but historically the United States has often taken a leadership or significant support role in international humanitarian efforts. However, this does not mean the U.S. always leads in every situation, as non-U.S. entities like the United Nations often play crucial roles in coordinating international disaster relief efforts. International responses usually observe the principles of state sovereignty and global cooperation, rather than any single nation's leadership.
Regarding President George W. Bush, it is generally false that he was a proponent of liberal internationalism, as his foreign policy decisions are more commonly associated with neoconservatism, which differs from liberal internationalism in its emphasis on unilateral action and democratic nation-building.