We know the US is brittle right now and its leadership and culture in disarray, its medical system disorganized and lacking. This MIGHT be an unexpected tipping point.
But imagine if the US fails to stem the infection quickly enough, and major population (i.e. economically contributing) centers end up having to be quarantined for an entire year while China recovers in 6 months.
But a once-mighty empire falls into decline because it lacks the resilience and vigor needed to address nominal collective threats - one blow reveals it to be the brittle, hollowed out shell it has become.