Since the attacks against Archbishop Burke are beginning yet again, especially since his article, The Discipline Regarding the Denial of Holy Communion to Those Obstinately Persevering in Manifest Grave Sin, do we not benefit by learning what the Church has always held, from the time of St Paul to the present? If so, allow me to share some insights from some commentaries concerning the 1917 Code of Canon Law. Archbishop Burke, in the article above, provides an excellent background on Canon 855 (1917) which has become Canon 915 in the new (1983) Code.
Can.855 §1 . The publicly unworthy, who are the excommunicated, the interdicted and the manifestly infamous, unless their penance and conversion have been established and they will have first made up for the public scandal, are to be excluded from the Eucharist.
§2. The minister is also to refuse occult sinners, if they request secretly and he will not have recognized them as converted; not, however, if they publicly request and he is not able to pass over them without scandal. 
From a book by the by Very Rev. H.A.Ayrinhac, S.S., D.D., D.C.L., we read, concerning canon 855, the following:
Source: Legislation on the Sacraments in the New Code of Canon Law
by Very Rev. H.A.Ayrinhac, S.S., D.D., D.C.L
And from Stanislaus Woywod, O.F.M., LL.B., in his "A Practical Commentary on the Code of Canon Law," we read:
Source: A Practical Commentary on the Code of Canon Law Volume 1
by Stanislaus Woywod, O.F.M., LL.B.,