As tensions rise in the Caribbean, we look at the legal authority for the fatal U.S. military attack on a boat President Trump said was carrying illegal drugs. Twenty-six nations pledge postwar security guarantees to Ukraine and wait to hear what the U.S. will contribute. Thailand elects a new prime minister, ditching the candidate of the Shinawatra family's once-dominant ruling party. And U.S. senators pit Robert F. Kennedy Jr. against Trump on vaccine policy in a heated Senate hearing. 

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