As he has on other occasions, Pope Benedict last Saturday cautioned a group of Brazilian bishops about the dangers of Marxist Liberation Theology and the grave consequences for ecclesiastical communities which embrace it. The Pope noted that it has been 25 years since the issuance of Libertatis Nuntius which highlighted the dangers of theologians uncritically using Marxist theses and methodologies.
Father Z has some pertinent commentary here.
I have always found it bleakly amusing that some Catholics on the Left have been attracted to an ideology which martyred so many Christians in the last century. Here is the text of Libertatis Nuntius: