Below is from a post by Fr. John Hunwicke's blog. He has some very good points, especially regarding the relevance of Vatican II in 2014.
"The biography of Archbishop Lefebvre by H E Bishop Tissier de Mallerais seems to me (who have no training in History) to be a finely detailed and balanced account of someone whom the author loved and respected, but with regard to whom he was determined to find out the truth. So one can find in this book a very 'conflicted' person. Sometimes he seems to be leaning over backwards to show proper deference to the Vicar of Christ; on other occasions, he seems almost sedevacantist (ET p 549 "the See of Peter and posts of authority in Rome being occupied by anti-Christs ..."; et cf ex gr pp 487, 506, 508). I do not see this inconsistency as unforgivable. The Archbishop was reacting to an ecclesial situation which has little parallel in the more recent history of the Church and accordingly has few guidelines provided for it in Canon Law and the Manualists. And the p 549 I cite in my parenthesis follows closely upon the Assisi Event; one can understand why the vision of the Antichrist, sitting where he ought not, should have been particularly in Lefebvre's mind. But he remained firmly and resolutely opposed to the seductions of sedevacantism at a time when a lesser man might have sought its easy and 'logical' solution.
However, the result remains that there is an incoherence of Ecclesiology at the heart of Lefebvre's construct. A real pope's actual wishes are disregarded; a situation not easily balanced by the Society's fierce loyalty to popes and bishops whose voices are muted by death. Conciliarism was defeated finally by making it a canonical offence to appeal from a living Pope to a hypothetical Council; appealing from a living Pope to his predecessors is not without its awkwardness.
But perhaps we should attempt a broader canvas. The history of earlier centuries does provide examples of behaviour, not much less uncanonical than Lefebvre's, which was subsequently validated by History. The Avignon exile and the Great Schism of the West afford a veritable laboratory of confused crises in which tidy solutions were beyond the grasp of good men and eventually order was restored by untidy expedients. These were not neat solutions; but perhaps a possibility for untidiness is sometimes the only sort of solution available to Christians in via. One thinks also of what happened in Czechoslovakia during the Cold War; what has happened in China during the last two decades. There is every reason to feel that the ecclesiological problems in the position of SSPX would disappear as SSPX lived in the fullest communion with the Petrine See.
Three final factors which in my view point towards the propriety of a generous approach to the SSPX, and a gracious receptivity on the part of the Society, and towards a cessation of any tendency to persecute institutes or individuals in the Catholic Church for a crime of Cryptolefebvrianism.
Many wonder what good the Ecumenical Movement has done. It hasn't even had the result of preventing ecclesial bodies from introducing new divisive measures, such as women's ordination. But this very ineffectiveness surely points to the one great big message we could and should all learn from the Ecumenical Movement: that the longer a division lasts, the more deep-rooted becomes the habit of separation and, in practical and human terms, the more unlikely it becomes that a reconciliation can ever happen.
Secondly: Summorum pontificum confirmed juridically that the Latin Church had lived for some four decades under the dominion of a lie. The Vetus Ordo had not been lawfully prohibited. Much persecution of devout priests and layfolk that took place during those decades is therefore now seen to have been vis sine lege. For this so long to have been so true with regard to the Holy Sacrifice of the Mass, which lies at the heart of the Church's life, argues a profound illness deep within the Latin Church. And the Big Lie was reinforced by multitudes of Little Lies ... that the Council mandated reordered Sanctuaries ... that the Council mandated exclusive use of the vernacular ... The de facto situation created by the Big Lie and the Little Lies combined ought not to be regarded as normative. Its questionable parentage must give it a degree of provisionality, even (perhaps especially) to those who find it comfortable to live with. The onslaught upon the Franciscans of the Immaculate suggests that there are those, high in the Church's administration, who have still internalised neither the juridical findings of Summorum pontificum nor its pastoral call for harmony.
Thirdly: Conciliar hermeneutics have moved on. I do not only refer to the teaching of Benedict XVI about 'Continuity' and 'Rupture' (although I think this is important and I was disappointed that spokesmen of the SSPX were more concerned to evade this discussion than to grab it and run with it). I mean also the much greater willingness among many to take a longer view of the Council. The more distant an object is down the lines of perspective, the smaller it appears to the eye (do you even know when the Council of Vienne was?). Benedict XVI echoed Newman's celebrated remarks about what unpleasant events councils have generally been and how harmful; and theologians are much less nervous now about admitting the existence even of textual problems within Vatican II itself. Arguably, Councils are best kept up the sleeve of the Sovereign Pontiff. Our present Holy Father had not been long on the Throne of S Peter when he commented on the facile optimism of Vatican II and opined that we are not so naive today (does this make him a Cryptolefebvrian?). At the heart of this question is a really very obvious and simple truth: the Council earnestly and laudably desired to engage with the mundus hodiernus, the mundus huius temporis, and with nostra aetas; but we are not now still in the mundus or aetas of the 1960s. The Council of Vienne, like Vatican II a largely practical Council, happened 700 years ago, but it took much less time than that for it to recede so far as to disappear off the Church's horizons; and it is a long time since anybody was required to eat humble pie with regard to its Conciliar documents, the "Spirit of Vienne", and "the entire post-Viennian Magisterium". Time itself possesses a quasi-Magisterial status, and I think enough time has elapsed since Vatican II to enable us to ... No: I will most certainly not say 'to renounce it'. After all, when Philip IV collected money for a crusade within six years and then simply embezzled that money together with the wealth he had looted from the Templars, I do not know that the Holy See thought it appropriate to annul the proceedings of Vienne. No; it is time simply to move on from the 1960s to the mundus hodiernus and the nostra aetas of 2014. When an elderly ball has been kicked around for long enough, sensible schoolboys leave it to settle quietly into the nutrients at the bottom of the ditch, unobserved except by the water voles, and agree to move on together to newer games. Whatever was of permanent value in Vienne ... and Vatican II ... has merged and disappeared gradually into what one might call the Church's general background noise (dogmatic decrees and anathemas of dogmatic councils are, of course, a different matter). What was unhelpful in the Conciliar texts or their consequences ... and when the Templars were led out to be burned, they probably thought that was unhelpful ... Time has purged away; or will purge.
Why cannot Roman dicasteries, and the SSPX, be content with that? Could each of them not name new questions of today which are much more pressing than the Suppression of the Templars, whether President Hollande should lead a new crusade to liberate the Holy Land, or even whether in the Latin Church the Pipe Organ should be held in high esteem (Sacrosanctum Concilium 120)?"