Nukes all around? A fraying U.S. nuclear umbrella is pushing allies to weigh defense options, raising risk of a proliferation cascade

Several U.S. allies are evaluating independent nuclear weapons development as American security commitments face scrutiny. Japan, South Korea, and Poland have publicly discussed nuclear capability options in recent years. This shift follows U.S. withdrawals from or reduced participation in arms-control agreements and statements questioning long-standing defense partnerships.

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