With their hopes of Commonwealth realm status through a settlement with Britain dimming, Smith and the RF began to seriously consider the alternative of a republic as early as December 1966, after the "Tiger" talks. Republicanism was presented as a means to clarify Rhodesia's claimed constitutional status, end ambiguity regarding ties with Britain and elicit official foreign recognition and acceptance. Smith's government began exploring a republican constitution in March 1967. The Union Jack and Rhodesia's Commonwealth-style national flag—a defaced Sky Blue Ensign with the Union Jack in the canton—were formally superseded on 11 November 1968, the third anniversary of UDI, by a new national flag: a green-white-green vertical triband, charged centrally with the Rhodesian coat of arms. After the electorate voted "yes" in a June 1969 referendum both to a new constitution and to the abandoning of symbolic ties to the Crown, Smith declared Rhodesia a republic on 2 March 1970. The 1969 constitution introduced a President as head of state, a multiracial senate, separate black and white electoral rolls (each with qualifications) and a mechanism whereby the number of black MPs would increase in line with the proportion of income tax revenues paid by black citizens. This process would stop once blacks had the same number of seats as whites; the declared goal was not majority rule, but rather "parity between the races".