Phibun's return to power coincided with the onset of the Cold War and the establishment of a Communist regime in North Vietnam. He soon won the support of the U.S., beginning a long tradition of U.S.-backed military regimes in Thailand (as the country was again renamed in July 1949, this time permanently). Once again political opponents were arrested and tried, and some were executed. There were attempted counter-coups by Pridi supporters in 1948, 1949 and 1951, the second leading to heavy fighting between the army and navy before Phibun emerged victorious. In the navy's 1951 attempt, popularly known as the Manhattan Coup, Phibun was nearly killed when the ship he was held hostage aboard was bombed by the pro-government air force.