In 1955, Thailand began to see a change in its economy fueled by domestic and international politics. The power struggle between the two main factions of the Phibul regime—led by Police General Phao Sriyanond and General (later, Field Marshal) Sarit Thanarat—increased, causing Sriyanonda to unsuccessfully seek support from the US for a coup against Phibulsongkram regime. Luang Phibulsongkram attempted to democratize his regime, seeking popular support by developing the economy. He again turned to the US, asking for economic rather than military aid. The US responded with unprecedented economic aid to the kingdom from 1955 to 1959. The Phibulsongkram government also made important changes to the country's fiscal policies, including scrapping the multiple-exchange-rate system in favor of a fixed, unified system which was in use until 1984. The government also neutralized trade and conducted secret diplomacy with the People's Republic of China, displeasing the United States.