If you belong to the rejectionist right, if you are Mangosuthu Buthelezi or General Constand Viljoen, Mr Kasrils is the embodiment of the one certainty to which, in muddling times, you tenaciously cling: that the South African Communist Party (SACP), masquerading as the African National Congress (ANC), will come to power after the April elections; that the new constitution to be unveiled this week is tailormade to accommodate its Stalinist schemes.
When you argue with right-wingers that Joe Slovo, the SACP chairman, described in Playboy this week as a 'teddy-bear terrorist', has emerged as perhaps the most moderate voice in the ANC alliance, they invariably reply: 'Aha] But what about Ronnie Kasrils?' The question is not so easy to dismiss.
A member of the SACP 'politburo', he serves also on the ANC's national executive and its shadow cabinet, the National Working Committee. One of the first active members of the ANC's armed wing in the early Sixties, he went into exile in 1963, spending many of the next 26 years in London, the rest either in the Soviet Union or in ANC camps in southern Africa. In 1989, before the unbanning of the ANC, he entered South Africa illegally, remaining underground for the next two years in his capacity as a senior intelligence officer of Umkhonto weSizwe (MK), the ANC's military wing.
In November 1991 Mr Kasrils, 'the Red Pimpernel', officially became public enemy No 1 described by the police in news broadcasts as 'armed and extremely dangerous'. A year later, no longer a wanted man, he led the charge at the ANC march in Bisho, which prompted the Ciskei army to open fire and kill 27 unarmed demonstrators. Blamed by the government and much of the media for the massacre, the charge only reinforced his credentials as a hero of the township youth. White, 55, not as slim as he once was, he remains young at heart, the living, fist-punching image of Paris 1968 in his trademark T-shirt and bruised brown leather jacket. He is also a devoted Arsenal supporter.
The first time I met him was in 1991, in a Johannesburg park, when he was still underground. We spent half the interview talking about football. When I visited him for lunch at his small home in a middle-class Johannesburg suburb earlier this month, the contradiction between Arsenal's recent success in Europe and their woeful incapacity to score goals in the British league kept us going through various platefuls of beef, Boerewors and a bottle of white wine.
Eventually we got around to Communism and its future. 'When Mao was asked what he thought of the French Revolution, he replied that it was too early to tell. People now say Communism is in the rubbish heap of history but humanity's idealism for a better system, shorn of exploitation and war, is going to reassert itself - and maybe in a shorter period than we think. Capitalism for me can't answer the problems. Of course, we must re- examine the concept of socialism as opposed to Stalinist mechanism. But I've got an optimistic belief that the socialist movement will come up with the right formula, one where socialism emerges out of democracy and not through imposition.'
The ANC he sees as a social democrat organisation, which today has subordinated some of its idealism to the practical requirements of reaching a political settlement with the white state. Did he feel uncomfortable towing the pragmatic line?
'Not so much. I think we're going through the eye of the needle right now and I think Mandela has been incredibly successful. Since the mid-Eighties, when he began his dialogue with the regime, he's shown an incredible understanding of the power equation. We had a different impression in exile. I was very committed to insurrection but I see now that it would have taken 20 more years. Now we're in the five-month countdown to the elections and then we'll be through the eye of the needle.
'We're coming to the breakthrough even if it will be a five-year coalition. But it does seem to me, romantic and revolutionary as I am, that this is the best way. I have no doubts about that - so long as we remain fixed to the principle of the upliftment of the impoverished majority. Our challenge - it's a tremendous challenge - is whether we'll be deflected from that.'
How would he define failure?
'What I fear for the ANC and the party is co-option into the corporate structure. My nightmare is that we'll maintain the beautiful revolutionary rhetoric and nothing else.'
What would he do about it?
'Pablo Neruda said there were three things in life that mattered, politics, poetry and love - and you can add sport to that. For me, I've been involved in the struggle for 30 years for one person one vote and I'm prepared, even if it's my swansong, to give my all to ensure we win the biggest vote in the elections. After that, well, we'll see what I do. The ANC will be big, like Celtic or Rangers, the winning team. The danger is that the party will be relegated to the second division. We must ensure that the embers of socialism are kept alive.'
No chance, then, that the flames of Stalinism will engulf South Africa after the elections?
He chuckles. 'What we need to do is keep to our principles and our idealism. The way I do that nowadays - I don't mind if I'm referred to as a romantic - is by reading Byron and Shelley. I read their poetry all the time - that's what motivates me, not an apparatchik attachment to a grey flag and Stalinism.'
Ronnie Kasrils's book 'Armed and Dangerous' is published this month by Heinemann