The ROC and the US signed a formal treaty of commerce and navigation in 1948. ROC passport holders can thus be granted an E1 and E2 Visa, with indefinite renewal status, based on continued operation of their enterprise in the US. In 1979 the US recognised the PRC instead of ROC. Commercial (such as Trade and Investment Framework Agreement signed in 1994, TIFA), cultural and other substantial relations are currently governed, inter alia, by the 1979 Taiwan Relations Act. The Act does not recognise the terminology of "Republic of China". United States policy does not support or oppose Taiwan's independence; instead U.S. policy takes a neutral position of “non-support” for Taiwan's independence.