Modern vice presidents can trace much of their political influence to the broad reforms that Jimmy Carter and Walter Mondale made to the second-highest elected office in the late 1970s.

Turkey’s geography and membership in NATO have long given the country an influential voice in foreign policy, but the assertive policies of President Erdogan have complicated its role.

The Caribbean island, which shares a close yet fraught relationship with the rest of the United States, faces a multilayered economic and social crisis rooted in long-standing policy and compounded b…