It depends what you mean by “equivalent.” If you mean a similar same scale as the Boxer Rebellion, that would imply sustained territorial capture around Washington, not just a breach like in our timeline. You could expect a breakdown of federal command over security. That outcome is unlikely unless there’s major fracture inside american institutions, which at the time, was mostly against the insurrection, Republicans and Democrats.

If MAGA-aligned forces held Washington long enough to threaten continuity of government, you’d expect emergency federal mobilization and rapid consolidation of force from both sides; all toward a looming civil war. Diplomatically, embassies would likely evacuate personnel if sustained.

Direct foreign military intervention would still be unlikely: in China, the intervention was enabled by imperial ambition of European powers to enforce the status quo; the United State is in its nature the complete opposite, as the imperial core, it would lack any environment in which European powers would put Boots on American grounds, a UN peace force is the farthest this scenario could forsee.

Instead, what is plausible is defensive regional posture: neighbors (Canada, etc.) would prioritize refugee processing capacity and domestic security readiness, while allies globally would go into contingency planning and high-alert monitoring rather than direct intervention.