Up and until 1958, small-scale military campaigns between the ROC forces and the People's Liberation Army (PLA) were carried out across the strait, which lasted until the Second Strait Crisis. From that point on, both sides of the strait have ceased all major hostilities against each other. The government under the Kuomintang, through its enforcement of martial law, kept a powerful hold on the state and its people throughout the Cold War. Because the Republic of China was under authoritarian rule, any perceived opposition to the government was considered illegal and dealt with harshly. A number of unsuccessful plots were made by the CIA to remove Chiang from power and replace him with a more pliant and less authoritarian leader. Chiang for his part never fully trusted US intentions and was wary of excessively pro-American politicians.