The Roosevelt Corollary depended on more than announcing an American enforcement role. Victory over Spain was an inadequate benchmark because Spain was widely regarded as a weakened European power with serious institutional and military problems. Other governments therefore still had reason to question whether Washington could sustain a wider hemispheric commitment. The Great White Fleet addressed that credibility gap by demonstrating concentrated force and long-distance operations in public view.
Notable Point · 18:01-19:26
Why defeating Spain did not settle American credibility
The Spanish-American War proved the United States could defeat Spain, but Roosevelt still needed to convince stronger European powers that American naval commitments were credible.