Tyler extended the doctrine into the Pacific

In 1842, President John Tyler applied Monroe-style exclusion to Hawaii and warned against British interference. Britain had visited and traded with the islands for decades and could have taken them earlier if it had considered Hawaii essential to its routes. Telling Britain not to acquire something it did not want cost London little, but the warning also signaled to Prussia and other interested powers that the United States claimed a Pacific security interest. The episode shows how policymakers could widen Monroe's language geographically while relying on a favorable balance of other powers' interests.