Thirty years after the publication of Unity of the Churches: An Actual Possibility by Karl Rahner and Heinrich Fries, our panel was asked whether we consider the unity of the churches an actual possibility today. I sketch an answer to this question with the help of Michael Kinnamon, past Executive Secretary of the World Council of Churches and from 2007–2011 the General Secretary of the National Council of Churches in the USA, and Cardinal Walter Kasper, President of the Pontifical Council (...) for Promoting Christian Unity from March 2001 through June 2010. In response to Cardinal Kasper’s caveats, I address three points: 1) the word of God and the Eucharist, 2) transubstantiation, and 3) the sacrifice of the Mass, The fourth point is my concluding answer to the question of Christian unity. (shrink)