In this series of posts, we have looked at the various ways in which Article X of the Constitution of the Episcopal Church (USA) provides for adding to or amending the Book of Common Prayer. We saw that revisions to the actual text of the BCP itself require passage in both Houses by a simple majority at each of two successive General Conventions (with the majorities in the House of Deputies at the second reading being determined both by orders of lay and clergy separately, and by a majority of the Dioceses represented in each order).
We saw further that liturgies and supplemental rites for particular occasions may also be approved on a trial basis for the whole Church in a single Convention, but only with a super-majority in the House of Bishops, consisting of one more than half of all Bishops with seat, voice and vote in the House -- whether they are present or not.
And finally, we saw that Article X recognizes discretion in each individual Bishop to approve rites "for special occasions" in their own Diocese only, provided that such special rites are consonant with the Canons and the Rubrics of the BCP. (All three of of these provisions in Article X took their present form after an amendment was passed on first reading in 1982, and was finally adopted in 1985.)
Along the way, it is important to note that there have been a number of attempts through the years to further amend subparagraph (c) of Article X to allow General Convention free rein to approve any kinds of trial rites for the Church, on such terms as it specified. See Resolution A-191 approved in 1991, which was rejected on second reading by both orders in the House of Deputies in 1994. The same language was adopted again in 2000, but rejected again in 2003 (this time, by the House of Bishops).
So General Convention's powers regarding trial liturgies remain constrained to what we discussed in Parts I and II of this series. To sum them up: it may approve any rites for supplemental or trial use if it adheres to the procedure in the second paragraph of Article X (requiring the supermajority in the HoB), but it otherwise may adopt only such Canons as may authorize individual Bishops to adopt trial rites in their own Dioceses, but only if those individually authorized rites are consonant with the Rubrics of the BCP.
As many may already know, the Church Publishing Company has published for many years several editions of a work called "The Book of Occasional Services." Its first edition appeared in 1914 under the title "A Book of Offices / Services for Occasions not Provided in the  Book of Common Prayer." A second edition was authorized and published in 1949. And in 1979, in connection with the adoption by General Convention of the new BCP, a new edition was authorized under its current title, The Book of Occasional Services.
A further supplemental liturgy series, called Enriching our Worship, grew out of the movement which started in the 1970s to make all official Church documents less patriarchal by changing their language to be more "inclusive." At GC68 in 1985, the Convention removed all the gender-specific language from its ordination canons in Title III, and also adopted Resolution A095, which directed what was then the Standing Liturgical Commission "to prepare inclusive language texts for the regular services of the Church." The Resolution cited for its authority Article X and Canon II.3.6, whose first subsection stated then (as it does now):
(a) Whenever the General Convention, pursuant to Article X of the Constitution, shall authorize for trial use a proposed revision of the Book of Common Prayer, or of a portion or portions thereof, the enabling Resolution shall specify the period of such trial use, the precise text thereof, and any special terms or conditions under which such trial use shall be carried out.Thus Resolution A095 was adopted by GC68, which envisioned that it would invoke its "trial use" authority under the second paragraph of Art. X when the Standing Liturgical Commission had developed the "inclusive texts" for Morning and Evening Prayer, and the Holy Eucharist, and recommended them to General Convention for adoption. And this is exactly what happened, starting with GC69 in 1988, and ongoing ever since. The collection of such trial services was renamed Enriching our Worship beginning in 1997.
From this history, it is clear that General Convention acted to authorize the rites in The Book of Occasional Services and Supplemental Liturgical Services / Enriching our Worship under the procedures spelled out for adopting liturgies for trial use in the second paragraph of Art. X of the Constitution. How could it do that, beginning in 1914 (as we have seen), and continuing down to 1988?
The answer will be obvious to anyone who reflects on the relatively small size of the House of Bishops during all those years. There were many fewer resigned (retired) Bishops back then, and to achieve a majority vote by all the Bishops entitled to vote, whether present at the meetings or not, was no great difficulty. In 1988, there were only 175 members in the House of Bishops, of whom nearly half were diocesans; together with the suffragans, assistants and coadjutors who attended General Convention, the House easily satisfied the supermajority requirement to approve trial rites for that year.
Once such trial rites are authorized by the required votes of both Houses of General Convention, continuing to amend and supplement them in subsequent years is covered by this subsection of Canon II.6.3:
(c) During the said period of trial use and under the modifying conditions specified, only the material so authorized, and in the exact form in which it has been so authorized, shall be available as an alternative for the said Book of Common Prayer or the said portion or portions thereof; Provided, however, that it shall be competent for the Presiding Bishop and the President of the House of Deputies, jointly, on recommendation by a resolution duly adopted at a meeting of the Standing Commission on Liturgy and Music communicated to the said presiding officers in writing, to authorize variations and adjustments to, or substitutions for, or alterations in, any portion of the texts under trial, which seem desirable as a result of such trial use, and which do not change the substance of a rite.Thus, it did not need the vote of General Convention to authorize additions and changes to the trial use materials once they had been approved, and continuing through the period of their authorization; the authority of the Presiding Bishop and the President of the House of Deputies, acting jointly at any time during that period, was enough. Nevertheless, General Convention continued to pass resolutions from time to time authorizing additional supplemental rites, and specifying new periods for their validity (usually just one triennium). And until recently, there were more than enough Bishops attending each General Convention to satisfy Article X's requirements for the approval of supplemental rites for trial use -- moreover, the materials approved were not as controversial as the ones being considered now.
In the period between 1988 and 2009, the membership of the House of Bishops nearly doubled, from 175 to nearly 300. According to the Journal of GC75 in 2006, the House of Bishops had 281 voting members, of which 138 were resigned from their jurisdictions. 120 of the 125 active Bishops attended, plus another 80 or so of the retired Bishops, so once again there were enough to make a supermajority.
For this General Convention in 2012, however, ENS reports that only "upwards of 200 Bishops" are expected to attend, or about the same number as in 2006. In the meantime, however, the total membership of the House has grown to just over 300 (eight more Bishops will be confirmed at the Convention itself, but will not be seated until they have been ordained). With a little over 300 total members, the required majority to approve same-sex rites will be on the order of around 152 or so. Thus if around 50 or more Bishops vote against Resolution A049 to approve same-sex blessings, it will be defeated.
The vote could thus be close, and opponents will almost certainly call for a roll call vote. It has not yet been announced on what day the Resolution will be before the House of Bishops, because it has to clear the Committee on Prayer Book, Liturgy and Church Music first. A hearing before that Committee is scheduled for today, July 6 at 7:00 pm, and will be devoted only to that Resolution.
We will continue to follow the progress of A049 as it makes its way through the Legislative process.
[UPDATE 07/06/2012: I am informed by some Bishops present that the number attending GC77 in Indianapolis is only on the order of 160 or so. If that is the case, then A049 is in for trouble, because there will be more than 10, and as many as perhaps 25, votes against it in the HoB. We will have to watch carefully whether the Presiding Bishop and her Parliamentarian adhere to the express requirements of Art. X. If they apply its language as written, A049 will go down to defeat in the HoB.]
[UPDATE 07/07/2012: The Rev. George Conger has an updated report from the House of Bishops that agrees with my assessment above. He reports that 153 votes are needed to pass Resolution A049, but that there are only 165 Bishops attending the Convention, so that it will take only 13 or more votes against it to defeat the measure.]