During the 1960s, Hafez al-Assad rose to prominence in the Syrian government through the 1963 coup d'état, backed by the Ba'ath party. He then promoted Tlass to high-ranking military and party positions. In 1965, while he was Ba'athist army commander of Homs, Lieutenant Colonel Mustafa Tlass arrested his pro-government comrades. A 1966 coup by an Alawite-dominated Ba'ath faction further strengthened al-Assad, and by association Tlass. Tensions within the government soon became apparent, however, with al-Assad emerging as the prime proponent of a pragmatist, military-based faction opposed to the ideological radicalism of the dominant ultra-leftists. Syrian defeat in the 1967 Six-Day War embarrassed the government, and in 1968 al-Assad managed to install Tlass as new Chief-of-Staff. After the debacle of an attempted Syrian intervention in the Black September conflict, the power struggle came to open conflict.