The Botswana Democratic Party, which has governed the southern African nation since its independence in 1966, enters Wednesday’s national elections facing an unlikely threat to its grip on power: diamonds.

For generations, diamonds have been the beating heart of the economy of Botswana, which ranks as one of the world’s top two diamond producers, regularly competing with Russia. The diamond industry has transformed Botswana into a beacon of hope on the African continent, and what the World Bank considers an upper-middle-income country.

But a global decline in diamond demand has hit Botswana’s economy hard. That has only deepened financial hardship for a population in which many believe that the government has upset the nation’s great rise through corruption and bad administration.

Botswana’s reputation as a stable democracy is being put to the test this year amid questions about whether the governing party is using underhanded tactics to stay in power. The party is only one of several in southern Africa that have led their countries since the end of colonialism but have since struggled to deliver a better life for many.

President Mokgweetsi Masisi has been barnstorming the vast, sparsely populated country of 2.5 million, positioning himself and his party as agents of change — even though he has been in power for six years and his party for nearly 60.