Let me say that I agree with both Ronald Kent and Ken Casebeer strongly but with a somewhat different perspective, one that may be of use to the subscribers to our list, although I am sure there will be those who will disagree strongly
 
As I see it, there is no need for anyone  who is not some variety of  red baiter or fears to offend some variety of a red baiter  to be defensive about or apologize for Joe Slovo and the SACP. 
No more than there is any reason to be be defensive or apologize for the CPUSA, which  in its struggles to build anti-racist united fronts and peoples front movements and organizations shares a good deal with SACP, including  a common history of anti-Communist legislation aimed to destroying not only both parties but all mass organizations  of these peoples fronts by portraying them  as "fronts" for a Soviet directed  "world communist conspiracy."

First, the SACP-ANC alliance was essentially a united front which operated in the context of a racist dictatorship.  The ANC's socialist oriented Freedom Charter was the most tangible expression of that United Front.  It was not remarkable for individuals to be formal members of both groups in United Front situations where elections were not at issue(In China for example, there were during the United Front of the 1920s between Sun Yat-sen's Kuomintang and the Chinese Communist Party, this was fairly common).  These were very fluid situations, in which  in the 1920s the only major nation in the world which was advancing an anti-imperialist policy was the Soviet Union, in words and deed--in fact, even in words, ruling media portrayed imperialist policies in glowing terms throughout the Euro-American world   In South Africa, life for the opponents of apartheid was a little like life in Fascist Italy or Vichy France, where individuals and groups formerly opposed to each other(the ANC for example had rejected the SACP in the 1930s) where drawn together by common experiences against a common enemy 

Those who throw words like "Stalinism" either because they belong to rival left factions, or think that it is expected of them ,  might remember that there weren't in the 1950s and 1960s any "Trotksyist", Luxembourgist," "Democratic Left country  or organizations providing material aid, including arms to  the liberation struggle in South Africa.  That came from the Soviet Union and its allies, while the de jure and de facto support for the Apartheid regime came from the U.S-NAT0 bloc allies, consisting of the former colonial powers in Africa. . 
 
After it was revealed that the Central Intelligence Agency played a leading role in the capture of Nelson Mandela in South Africa an American reporter asked Marlin Fitzwater, George HW Bush's press Secretary replied testily that those events happened long ago in another administration.  When Mandela died, I wrote  on the Political Affairs Blog that such a formal apology would be a huge step forward for the Obama administration in Africa.  I guess now that it has been revealed that Nelson Mandela was a member of SACP at the time that will possibly become a justification for the CIA's actions, not only for the right but for old and new "cold warriors."  I still think that a formal apology from the U.S. government to South Africa for the CIA's actions is something that all labor and progressive activists in the U.S. should demand and it would be nice to see the New York Times join in that

The SACP like  majority  communist parties through the world, whatever their size, were part during and after the period of the Comintern of a world movement in which the Soviet Union was first the world's only socialist country and , then a great power offfering aid to a great many national liberation struggles in the world against  the capitalist/imperialist countries.  

That large and powerful Communist parties in France and Italy and other countries which were democracies and where they had democratic rights became critical of Soviet policies in the late 1950s and afterwards is understandable.  That Communist Parties like the SACP which faced the Suppression of Communism Act(1950) and multi-faceted repression in a "Master Race Democracy" where only whites could vote and the CPUSA which faced the McCarran Internal Security Act(1950) the Communist Control Act(1954) and multi-faceted repression is also or should be understandable.  

Cold war revival nonesense that seeks to discredit Nelson Mandela for his membership and involvement in the SACP and impose a posthumous "loyalty oath" on Joe Slovo  of the kind that provoked Ronald Kent's unpublished  reply to the NYT is a huge distraction from what were and are the real issues--that is the role of the U.S., Britain, and the rest of the former colonial powers in aiding and abetting the Apartheid Regime, which was hideous relic in its own way of Hitlerite fascism  for four decade.  
This was done first openly and then in less open ways, putting their money in South Africa even when their mouths were speaking against Apartheid, contending that their policies would "reform" apartheid while, in Apartheid's last years for example, the Reagan administration worked directly with it funding and helping to direct the bloody contra war in Angola.

To move toward  end this rather long and grim post on a somewhat lighter note, I like to say, when I am a called a "Stalinist," that "I am no Stalinist and neither was Stalin."  Joseph Stalin was the most important figure in the global Communist movement from the mid 1920s to his death in 1953.  His policies were all over the place in terms of tactics and strategies. The repressive acts,mass purges and arrests , policies of fear and intimidations,  violations of Soviet law, which his government always denied, were by no means unique either to his government and in history,  and  have always been used by  enemies of the Soviet Union  from all sides, both the real abuses and the imagined ones  don't amount to an ism, have been used and continue to be use  as a kind of political taboo.

Monday is Martin Luther King Jr day, a National holiday.  A formal apology from the FBI for its campaign of unrelenting harassment and abuse against Dr King, which has long been a matter of record but will I doubt be widely discussed on Monday, would also be a step forward.