For more than two decades, Washington and New Delhi built a strategic partnership that was hailed as one of the great success stories of post–Cold War diplomacy. Today, that relationship is facing its most serious test in years — and India is signaling it has other options.

China's ambassador to India, Xu Feihong, says China will stand firmly with India and opposes President Donald Trump's tariffs of up to 50% on Indian exports. Kate Kalutkiewicz, a former Trump trade official and Mclarty Associates lead for trade,