Damage Control by Shoghi Effendi

Abdu’l-Baha’s claim of infalliblity was directly opposed by his brother Mirza Muhammad Ali, resulting in the latter being declared a violator of Baha’u’llah’s Covenant, which was an outright lie. You don’t violate a covenant by upholding the actual teachings of Baha’u’llah!

A generation later Shoghi Effendi, Abdu’l-Baha’s grandson, had become Baha’i leader. Just as his grandfather had engaged in doublespeak to justify his absurd claim of infallibility, so likewise did the “Guardian”. In the book The World Order of Bahá’u’lláh, he had this to say about Abdu’l-Baha’s station:

An attempt I strongly feel should now be made to clarify our minds regarding the station occupied by ‘Abdu’l‑Bahá and the significance of His position in this holy Dispensation. It would be indeed difficult for us, who stand so close to such a tremendous figure and are drawn by the mysterious power of so magnetic a personality, to obtain a clear and exact understanding of the rôle and character of One Who, not only in the Dispensation of Bahá’u’lláh but in the entire field of religious history, fulfills a unique function. Though moving in a sphere of His own and holding a rank radically different from that of the Author and the Forerunner of the Bahá’í Revelation, He, by virtue of the station ordained for Him through the Covenant of Bahá’u’lláh, forms together with them what may be termed the Three Central Figures of a Faith that stands unapproached in the world’s spiritual history. He towers, in conjunction with them, above the destinies of this infant Faith of God from a level to which no individual or body ministering to its needs after Him, and for no less a period than a full thousand years, can ever hope to rise. To degrade His lofty rank by identifying His station with or by regarding it as roughly equivalent to, the position of those on whom the mantle of His authority has fallen would be an act of impiety as grave as the no less heretical belief that inclines to exalt Him to a state of absolute equality with either the central Figure or Forerunner of our Faith. For wide as is the gulf that separates ‘Abdu’l‑Bahá from Him Who is the Source of an independent Revelation, it can never be regarded as commensurate with the greater distance that stands between Him Who is the Center of the Covenant and His ministers who are to carry on His work, whatever be their name, their rank, their functions or their future achievements. Let those who have known ‘Abdu’l‑Bahá, who through their contact with His magnetic personality have come to cherish for Him so fervent an admiration, reflect, in the light of this statement, on the greatness of One Who is so far above Him in station.
That ‘Abdu’l‑Bahá is not a Manifestation of God, that, though the successor of His Father, He does not occupy a cognate station, that no one else except the Báb and Bahá’u’lláh can ever lay claim to such a station before the expiration of a full thousand years—are verities which lie embedded in the specific utterances of both the Founder of our Faith and the Interpreter of His teachings.
“Whoso layeth claim to a Revelation direct from God,” is the express warning uttered in the Kitáb-i-Aqdas, “ere the expiration of a full thousand years, such a man is assuredly a lying imposter. We pray God that He may graciously assist him to retract and repudiate such claim. Should he repent, God will no doubt forgive him. If, however, he persists in his error, God will assuredly send down one who will deal mercilessly with him. Terrible indeed is God in punishing!” “Whosoever,” He adds as a further emphasis, “interpreteth this verse otherwise than its obvious meaning is deprived of the Spirit of God and of His mercy which encompasseth all created things.” “Should a man appear,” is yet another conclusive statement, “ere the lapse of a full thousand years—each year consisting of twelve months according to the Qur’án, and of nineteen months of nineteen days each, according to the Bayán—and if such a man reveal to your eyes all the signs of God, unhesitatingly reject him!”
‘Abdu’l‑Bahá’s own statements, in confirmation of this warning, are no less emphatic and binding: “This is,” He declares, “my firm, my unshakable conviction, the essence of my unconcealed and explicit belief—a conviction and belief which the denizens of the Abhá Kingdom fully share: The Blessed Beauty is the Sun of Truth, and His light the light of truth. The Báb is likewise the Sun of Truth, and His light the light of truth… My station is the station of servitude—a servitude which is complete, pure and real, firmly established, enduring, obvious, explicitly revealed and subject to no interpretation whatever… I am the Interpreter of the Word of God; such is my interpretation.”
Does not ‘Abdu’l‑Bahá in His own Will—in a tone and language that might well confound the most inveterate among the breakers of His Father’s Covenant—rob of their chief weapon those who so long and so persistently had striven to impute to Him the charge of having tacitly claimed a station equal, if not superior, to that of Bahá’u’lláh? “The foundation of the belief of the people of Bahá is this,” thus proclaims one of the weightiest passages of that last document left to voice in perpetuity the directions and wishes of a departed Master, “His Holiness the Exalted One (the Báb) is the Manifestation of the unity and oneness of God and the Forerunner of the Ancient Beauty. His Holiness the Abhá Beauty (Bahá’u’lláh) (may my life be a sacrifice for His steadfast friends) is the supreme Manifestation of God and the Day-Spring of His most divine Essence. All others are servants unto Him and do His bidding.”
From such clear and formally laid down statements, incompatible as they are with any assertion of a claim to Prophethood, we should not by any means infer that ‘Abdu’l‑Bahá is merely one of the servants of the Blessed Beauty, or at best one whose function is to be confined to that of an authorized interpreter of His Father’s teachings. Far be it from me to entertain such a notion or to wish to instill such sentiments. To regard Him in such a light is a manifest betrayal of the priceless heritage bequeathed by Bahá’u’lláh to mankind. Immeasurably exalted is the station conferred upon Him by the Supreme Pen above and beyond the implications of these, His own written statements. Whether in the Kitáb-i-Aqdas, the most weighty and sacred of all the works of Bahá’u’lláh, or in the Kitáb-i-‘Ahd, the Book of His Covenant, or in the Súriy-i-Ghusn (Tablet of the Branch), such references as have been recorded by the pen of Bahá’u’lláh—references which the Tablets of His Father addressed to Him mightily reinforce—invest ‘Abdu’l‑Bahá with a power, and surround Him with a halo, which the present generation can never adequately appreciate.
He is, and should for all time be regarded, first and foremost, as the Center and Pivot of Bahá’u’lláh’s peerless and all-enfolding Covenant, His most exalted handiwork, the stainless Mirror of His light, the perfect Exemplar of His teachings, the unerring Interpreter of His Word, the embodiment of every Bahá’í ideal, the incarnation of every Bahá’í virtue, the Most Mighty Branch sprung from the Ancient Root, the Limb of the Law of God, the Being “round Whom all names revolve,” the Mainspring of the Oneness of Humanity, the Ensign of the Most Great Peace, the Moon of the Central Orb of this most holy Dispensation—styles and titles that are implicit and find their truest, their highest and fairest expression in the magic name ‘Abdu’l‑Bahá. He is, above and beyond these appellations, the “Mystery of God”—an expression by which Bahá’u’lláh Himself has chosen to designate Him, and which, while it does not by any means justify us to assign to Him the station of Prophethood, indicates how in the person of ‘Abdu’l‑Bahá the incompatible characteristics of a human nature and superhuman knowledge and perfection have been blended and are completely harmonized.
“When the ocean of My presence hath ebbed and the Book of My Revelation is ended,” proclaims the Kitáb-i-Aqdas, “turn your faces towards Him Whom God hath purposed, Who hath branched from this Ancient Root.” And again, “When the Mystic Dove will have winged its flight from its Sanctuary of Praise and sought its far-off goal, its hidden habitation, refer ye whatsoever ye understand not in the Book to Him Who hath branched from this mighty Stock.”
In the Kitáb-i-‘Ahd, moreover, Bahá’u’lláh solemnly and explicitly declares: “It is incumbent upon the Aghṣán, the Afnán and My kindred to turn, one and all, their faces towards the Most Mighty Branch. Consider that which We have revealed in Our Most Holy Book: ‘When the ocean of My presence hath ebbed and the Book of My Revelation is ended, turn your faces towards Him Whom God hath purposed, Who hath branched from this Ancient Root.’ The object of this sacred verse is none except the Most Mighty Branch (‘Abdu’l‑Bahá). Thus have We graciously revealed unto you our potent Will, and I am verily the Gracious, the All-Bountiful.”

Infallibility means just that and once you claim it for yourself, you are claiming equal authority with God himself, period. If you turn around and claim to be less than God or Baha’u’llah in authority or others make that claim for you, that is a contradiction. One as absurd as the one Christians have made regarding the “Trinity”.
You can affirm that Abdu’l-Baha was the legitimate leader of the Baha’i community after Baha’u’llah and at the same time deny his claim of being infallible in any way, shape or form because THAT IS THE ONLY POSITION CONSISTENT WITH WHAT BAHA’U’LLAH WROTE!
Note how selective Shoghi Effendi was in quoting from the Kitáb-i-‘Ahd. He completely left out the following:

Verily God hath ordained the station of the Greater Branch [Muḥammad ‘Alí] to be beneath that of the Most Great Branch [‘Abdu’l‑Bahá]. He is in truth the Ordainer, the All-Wise. We have chosen “the Greater” after “the Most Great,” as decreed by Him Who is the All-Knowing, the All-Informed.

Because Shoghi Effendi’s very position as “Guardian of the Cause of God” was thus a violation of that very same Kitáb-i-‘Ahd!