Mark Lilla has given a rich and readable summary of the politics of Derrida in the poltical and philosophical context in which Derrida has been read.  Most of this is new to me.  Although I have read quite a bit of Derrida's early (pre-political work, according to Lilla) I ahve read almost none of his more political writings.  Nevertheless, I found Lilla's account compelling and what follows is an abbreviated paraphrase that focuses mostly on Lilla's account of Derrida and less on the political context in which Derrida has written: 

For three decades after the Second World War, all French philosophers were expected to take a political position on events of the day.  It was a tradition established by the venerable existentialist, Jean-Paul Sartre.  Still, a few philosophers (Levinas, Ricoeur) avoided avoided making political statements, and for a long time, Derrida was on this short list.  He avoided popular affiliations with the Communist party, for example, and he generally frustrated every popular attempt to discern his political position. 

Then, in the 1980's, when Derrida's popularity began to fade in France while it increased in the English speaking world, America put new pressures on Derrida to make his political commitments known.  After all, America  had imported Derrida as part of a new academic canon that was being called "postmodernism," and postmodernism, in this early movement, saw itself as highly political.  If Derrida was to be among the postmoderns, America needed to know what his politics were.  Still, as recently as 1990 Derrida had not explained his politics. 

But, now, Derrida has spoken.  Since 1990, Derrida has published six books on political isues, and two of them have already been translated into English: The Specters of Marx, and Politics of Friendship. 

What has emerged in this new political writing is a strange new use of theological language.  It is even difficult to know if Derrida means for us to take his new language literally. 

In this new political writing, Derrida says that there is no justice in the world and that it is our obligation to await await justice as the coming of the Messiah.  At sometimes it seems that our training for waiting is a practice in Derridean deconstruction, but at other times, he says, explicitly, if unconvincingly, that "deconstruction is justice." 

But however unclear we are as to exactly Derrida's political position, it is clear that Derrida wants his work to have a political interpretation that supports the political left, but how radical he wants it to be is not clear.  Is it liberal politics as Terry Eagleton suggests?  Or is it Marxist?  Derrida simply says that his position is in the spirit of Marxism although everything Marx wrote is rubbish. 

The political problem for Derrida is that everything deconstruction says is open to the same devestating deconstruction that can be applied to all others.  For political rhetoric, this is not good.  It means deconstruction cannot give its followers a rally cry or even simple reasons to pursue a particular political agenda.  To this criticism, Derrida argues back, that the one thing that remains irreducible to any deconstruction is a "certain experience of the emancipatory promise" that was sparked by Marxism -- although Marxism, as Marx conceived it, is now no longer something to follow. 

In other words, in the end, all Derrida seems to offer politics is a certain hope or vague promise that deconstruction will emancipate us.