South Africans go to the polls Wednesday in their fifth election since the end of apartheid. In any other democracy, a ruling party would rejoice if it could win 55 to 60 percent of the vote. Not so for South Africa’s African National Congress (ANC). It still presumes it deserves a massive victory simply for being the prime liberator from white rule two decades ago.

The ANC is still widely expected to win this election. But its leaders are bracing for the possibility of receiving less than 60 percent for the first time. Many young voters don’t buy into their parents’ argument of a “liberation debt” for the party’s role in freeing blacks. Instead, they see mainly corruption, lack of jobs, an unaccountable government – and a few alternative and promising political parties.

The pattern is not new. Many parties that liberate their countries from oppression take control of the state and then cling to power by living off past glory. They use their legacy to remain immune from competitive politics. In Africa, many postcolonial leaders fell into this trap. 

A current example is in Zimbabwe, where the main liberator from white rule, Robert Mugabe, has maintained a near-monopoly on power for more than three decades. The country’s economy has suffered for it.

South Africa need not go down this path. It could instead follow the example of Mexico, where the longtime ruling Institutional Revolutionary Party lost power in 2000 only to reform itself enough to win an election in 2011. It now leads the effort to transform the country.

A similar process could be under way in India for the ruling Congress party, which led the effort against British rule and was reelected during most of the country’s independence. It is expected to lose power in elections that end May 12. Many young voters are tired of the Nehru-Gandhi family dynasty that still ties itself to the anti-colonial struggle.

In Myanmar (Burma), the military ruled for decades by claiming the legacy of the leading anti-colonial fighter, Aung San. Only after his daughter, Aung San Suu Kyi, began to challenge that legacy in 1988 did the country start to slowly adopt democracy.

A liberation party usually warrants gratitude but only if it keeps a similar spirit of renewal once in power rather than drifting into arrogance and neglect. Countries, like cars, cannot be driven by looking into a rear-view mirror. A ruling party must be judged on its current merits at the ballot box.

During its early rule under Nelson Mandela, the ANC lifted up South Africa and kept racial harmony. But in recent years, especially under President Jacob Zuma, the party has faltered in its governance. It now more loudly claims a right to stay in power. In a speech last year, Mr. Zuma said: “There are many people who are forming unknown political parties, claiming these parties will help people – this is a dream. They’ll never do anything because they’ll never be in government.”

Hubris often builds up in those who rest on the laurels of being liberators. Yet democracy demands constant renewal through alternation in power. Eventually the ANC may fall if it does not first reform itself. The mantle of liberation will then rest on the voters.