Here's a remarkable and democratically depressing fact: South African voters rarely change their national government.
Under the whites-only franchise until 1989, the National Party won an extraordinary 11 consecutive elections.
Since the advent of full democracy in 1994, the ANC has won five polls on the trot.
The 40-plus percentage points separating the ANC from its nearest opponent, the DA, suggests the African Nationalists have even less to fear from their opponents than the Afrikaner Nationalists did.
There has been a more dramatic change at local level. But the results of the 2016 municipal elections were more a consequence of Jacob Zuma depressing turnout among his voters than huge shifts in political allegiance.
Of course, no national liberation government lasts forever.
Witness the demise of the Indian Congress Party or the Israeli Labour Party or the Mexican Institutional Revolutionary Party. But in each case it took three to seven decades to vote them out.
All this indicates the hard road the opposition has to walk in a country whose democratic present, like its undemocratic past, is in thrall to nationalist one-party domination.Recent events have thrown light on our two largest opposition parties.
This week, in the parliamentary precinct, EFF chief whip Floyd Shivambu demonstrated that a good education is no bar to physical thuggery.
But while the "anything goes" school of politics had some cachet when the delinquent Zuma ruled the roost, it is likely to be less impactful under Cyril Ramaphosa. His mastery of the political gesture and his "let us reason together" approach expose the EFF's hollow core.
If against the vinegary Zuma the EFF could not hit double figures at the polls, the political honey traps that Ramaphosa has set for his populist opponents suggest it will decline over time.
But an opportunist like Julius Malema certainly knows where opportunities lie. His calculation is to remove the DA in Nelson Mandela Bay, deliver it to the ANC, and leverage his low support there (5%) for bigger offers from Ramaphosa elsewhere.
The DA, three times larger than the EFF, is currently weathering a perfect storm, or a series of them. Events in Cape Town, the possible loss of Nelson Mandela Bay, the Ramaphosa relief rally and an upcoming congress have forced it to re-examine its core.
Its previous assumptions - one more heave to form a national governing coalition, perfect local alliances and secure an outright win in Gauteng - have moved from possible to improbable.
The contest at the DA April congress for the symbolic post of federal chairman of the party might shed light on how the party will confront the future without the gifts Zuma's misgovernance bestowed.
It needs to affirm its values, embed them into policies and be prepared for what veteran opposition leader Colin Eglin called "the politics of the long haul".
Incumbent chairman Athol Trollip has thrust himself into the national consciousness because of his doughty fight to prevail against the odds in Nelson Mandela Bay.When, over a decade ago, he was obscured from national view as provincial leader in Bhisho, I had an indication of his core offer.
As party leader then, I asked him to assist a Cape Town-based domestic worker with the urgent welfare needs of her father in the Eastern Cape. I arranged for Trollip to telephone her and they had a long-distance conversation.
Afterwards, I asked her how the discussion went. She advised a happy outcome, adding: "I never knew the DA had such good black leaders."
I informed her that, in fact, Trollip was white. Her rejoinder? "No white man speaks such good isiXhosa!"
Now Malema wants to (politically) "slit this white man's throat". And within the DA, his mayoral colleague from Tshwane wants Trollip's party job.
Trollip, though, exemplifies to his party and country an old poster from the Eglin era - one the DA might do well to refresh for the long journey ahead. It read "Merit, not Colour".
• Leon is a former leader of the opposition and former ambassador to Argentina..