For more than a year, U.S. officials have quietly asked themselves a question they would not dare pose in public: Could Russia’s botched invasion of Ukraine eventually lead to the downfall of Russian President Vladimir Putin?

For a few chaotic, head-snapping hours this weekend, the notion did not seem so far-fetched. But even with the apparent end to the immediate threat posed by Yevgeny Prigozhin’s rebellious mercenary army, the short-lived uprising suggested that Putin’s hold on power is more tenuous than at any time since he took office more than two decades ago.

The aftermath of the mutiny leaves U.S. President Joe Biden and U.S. policymakers with both opportunity and danger in perhaps the most volatile moment since the early days of the invasion of Ukraine. Disarray in Russia could lead to a breakdown of its war effort just as Ukrainian forces are mounting their long-awaited counteroffensive, but officials in Washington remained nervous about an unpredictable, nuclear-armed Putin feeling vulnerable.