BANGKOK -- Armed clashes have broken out between Thailand and Cambodia in long-disputed border areas, rapidly escalating months-long tensions.

But the fiery bout in Southeast Asia also marks a test for Washington's waning influence in a region viewed as a crucial theater in a geopolitical competition between the United States and China. "This crisis represents a critical test of American and Chinese influence in Southeast Asia,

A personal feud between two of Southeast Asia’s political titans is inflaming the worst violence on the Thailand-Cambodia border in more than a decade.