An Oil-Rich Ally Tests Its Relationship With the U.S.

The ruler of the United Arab Emirates, Sheikh Mohammed bin Zayed, is a key American ally who counts on the United States to defend his country.

But he has traveled twice to Russia over the past year to meet with President Vladimir V. Putin, and in June, his country was celebrated as the guest of honor at the Russian leader’s flagship investment forum. Later this month, the Emirati and Chinese air forces plan to train together for the first…