Covenants
[hope to do hyperlinks later]
I understand the Orthodox reticence in engagement with much of modern Bible/Talmud scholarship on many issues, and I think a hidden factor is the fear that not simply modern scholarship, but those who integrate scholarship into their faith communities (mainline and "historical" Christianity and to a degree liberal Judaisms - much less so Islam), may be [more] truthful in the Judaisms they account! Whole cans of worms are evidenced - and opened; from competing Judaisms to superseding Christianities to reconciliations unthinkable between theological, scholarship-averse fundamentalist "orthodoxies".

I believe that Orthodox Judaism, the various "liberal" Judaisms, Christianity (mainline and "Orthodox" - Catholic and Orthodox), and modern scholarship would all agree that JC could not reasonably be argued as the fulfillment of the "Jewish messiah" of contemporary historical Judaism ("Orthodoxy"). What is believed, what contemporary Jewish Jews abide, as far as mainline and historical Christianity and liberal Judaism are concerned - is "Rabbinic Judaism" - not Biblical Judaism.
They would all phrase this agreement differently - very differently, but I think it obvious they would agree. Orthodox Judaism would believe - apart from the others (who on the main accept evolution in interpretation, doctrine and belief regarding themselves), that contemporary doctrine has, for the most part, always been as it is; it is a history that is "special creation", at the very least essence and (to some large degree) substance 'down from Sinai' - in the loshon of Creationism. Perhaps spiced with Punctuated Equilibrium as a way to further explain their 'uniqueness' up and against the...umm...uniqueness...of others (emphasis on the useful, "special creation"-leaning misunderstandings of of Punc Eq - since Punc Eq cannot be claimed for only one species and no other without claiming the exception is a totally different organism in essence unlike any other - but when you do that, Punc Eq isn't being claimed for that species; special creationism is).

Think about it; historical, "Orthodox" Judaism is considered by these others in much the way modern scholarship accounts it; the canonization of orally and written "Pharisaic traditions" as "oral Torah", the result of a community accumulating and weeding texts (accumulating to the Masoretic text of Torah, Nevi'im and Ketuvi'im), beliefs and practices (Oral Law), over time - and changing/evolving in relationships between said texts, practices and beliefs, in the meanings held about such relationships - defining even itself in each new setting and era against "Others", whom they are not, etc. And at the same time, these faithful others regard it as deriving from Revelation, of the highest order.

BUT these scholarship-imbiding modern communities themselves, for decades now - and perhaps most interestingly where historical, Orthodox Christianities are concerned - believe and teach as doctrine that they are also communities that formed and evolved around their histories of their selected texts (on the same narratives, laws, etc), from the same eras - their readings and the accounted Judaism they have found. They not only concede this, they abide and teach this! They have involved [and, at times, to me quite convincing] accounts of their faith, faith refined by scholarship, by historical questioning - not challenged by it as the great number of Orthodox Jews have regarded such engagement (traditional Conservative Judaism - from the era of Orthodox condemnation of them...being an exception this). They have a centuries-long history of engaging each accumulating and receding era of scholarship, of philosophical insight on all things - often (in the Catholic example), responsible for the institutions where such exchange, debate and engagement transpired and was established. Key faithful figures in the hard sciences as well, that came to define the advent of science, of the modern era, etc, etc...

To my mind, Orthodox Judaism - b'klal - cannot concede a similar, co-committal evolution and accumulation and remain Orthodox.

In other words, what is perhaps most challenging to Orthodox Judaism about this is not simply the possibility that the Orthoprax or secular academics or scholars are correct in their scholarship - but that other academically-committed Faithful may, in key ways (historical points that defined them/us; 1st Century Judaism, 1st Century Christianity), be correct in their faiths - their Orthodoxies - which, on the main are integrations and reconciliations of modern scholarship with historical faith and practice.

I think it goes unnoticed as a challenge, because these 'competing' faiths - unlike Evangelicals - aren't interested in converting Jews to their faith modalities; many have even proclaimed the permanence of the Jewish covenant and expressed ill-ease with seeking the conversion of Jews, so far as a willingness to accept them as individuals, but not seeking them out as such (The Catholic Church has an articulated eschatology that puts the fate of the majority of the Jews in God's perview - not mans; they no longer sanction "mission to the Jews", and repudiate such historical venture as having been done in theological error).

Such an approximating self-perception, Orthodox Jews, as a communal system, cannot abide. In fact I have only encountered individual Jews that conceive of reconciliations, often piecemeal.

Within this is also the challenge that mainline/historical Christianities and liberal Judaisms have fully-integrated beliefs about the salvific efficacy of other belief systems - and they include a place for Orthodox Judaism. Salvific potential, I grant - but it's there, in their Catechisms, their council decrees. The God they believe in (at least as in the Orthodox, historical Christianities) is one you cannot tell what to do or how to do it - a pretty big God!; for Orthodox Judaism, halacha seemingly is just such a "telling" of what God can do - how and when; the chutzpah of it sounds attractive to people (Gerim?...utterly-assimilated BTs?..) who come from backgrounds which they believed belittled humanity (one way or another) - such chutzpah is quite a bestowal of significance to humankind! (at least the Jews among humanity...) -

but so (Christianity might respond), is God becoming man, amidst 1st Century Judaism, seemingly least-prepared (in Orthodox Jewish "historiography"), for such a claim to occur, but not "unheard of" for Pagans, right?...were even they expecting something quite like this...from the Jews?...C.S. Lewis (all of ch. 14 is relevant, but here's snippet);

"From a certain point of view Christ is 'the same sort of thing' as Adonis or Osiris (always, of course, waiving the fact that they lived nobody knows where or when, while He was executed by a Roman magistrate we know in a year which can be roughly dated). And that is just the puzzle. If Christianity is a religion of that kind, why is the analogy of the seed falling into the ground so seldom mentioned (twice only if I mistake not) in the New Testament? [the only documental source for what can assuredly be called Christianity; the Christian Scriptures would seem to sell themselves short by not emphasizing more strongly to their neighbors the pagan cognates between their faiths!!] Corn-religions are popular and respectable: if that is what the first Christian teachers were putting across, what motive could they have for concealing the fact? The impression they make is that of men who simply don't know how close they are to the corn-religions: men who simply overlook the rich sources of relevant imagery and association which they must have been on the verge of tapping at every moment...Why should the only religion of a 'dying God' which has actually survived and risen to unexampled spiritual heights occur precisely among those people to whom, and to whom almost alone, the whole circle of ideas that belong to the 'dying God' was foreign?" ..The records, in fact, show us a Person who enacts the part of the Dying God, but whose thoughts and words remain quite outside the circle of religions ideas to which the Dying God belongs...It is as if you met the sea-serpent and found that it disbelieved in sea-serpents."
-C.S. Lewis, Miracles, ch. 14, "The Grand Miracle"

This would explain the surprise of even JC's own family and disciples to his statements and actions taken as one kind of whole - a whole The Church established as the NT Scriptures. Which can lead to C.S. Lewis' famous "Trilemma" - or a quadrilemma (the other competing 'quadrilemmas' - that the accounts 'aren't accurate' seems to deny a place for 'Holy Tradition' - the Christian equivalent of "Oral Torah" - and the supposition that JC never existed as a person are argued all over the net);

...either Jesus was right, mad, or lying. Rabbi Soloveichik clearly rejects the first option but delicately—and no doubt wisely—declines to call Jesus either mad or demonic, although by his own account it would seem he has no other choice. But the New Testament [itself...] narrates another option. To be sure, the gospels recognize something like a trilemma, since they report that Jesus' own family (however defined) thought he was mad (Mark 3:21), while his opponents claimed he came from the devil (Mark 3:22). But even among Jesus' closest followers [the kind of traditional Jews accounted above by Lewis], the most common reaction was incomprehension. It would do great violence to the evidence of the gospels (including the Fourth Gospel) to assert that the disciples accepted Jesus as God simpliciter by the mere fact that they were his disciples. For one thing, important strains in the New Testament tradition assert that Jesus was made Lord and Christ in the Resurrection (Acts 2:36, Rom. 1:3-4), however that “making” is to be understood [which if considered could 'explain' other discrepancies in his self-perception and those of others before and after and the account of him in the later NT works]. Let us call this, then, the New Testament “quadrilemma.” I draw attention to this theme of incomprehension...to point out the inadequacy of Lewis' more truncated and simplistic trilemma. For one thing, Christians hardly want to box Jews into either accepting Jesus or calling him mad or demonic. After all, who does not, ultimately, find Jesus baffling?

I do think Jewish Anti-Missionaries fail in many, many ways - but ignoring these responses to challenges, actually made before the challenges were issued by the Anti-Missionaries?...available for all of them to read? And it matters so much - as the general narrative of JC has been reconciled by historical Christianities with modern scholarship - where much of historical Judaism cannot reconcile itself as consistently or communally to even the historical accounts made of Judaism - without pushing the "Conservative" side of the Orthodox envelope.

My response would be some formulation of "Israel", in the collective, being this similarly-baffling, similarly-mythic personage - but I haven't formulated it yet.

In addition, liberal Orthodox Judaisms have been considering "dual covenant" theologies whereby Jews may be "more" right than others, these self-same others have, often for decades now - already done the same regarding Orthodox Judaism, other Christianities - some even regarding other faiths. On the main, without recourse to "relativism" or liberalism in doctrine.
To engage in dialogues or interactions where such conversations could occur looks scary for those who prefer "dueling covenants" - fundamentalist Evangelicals, historical schismatics - and Orthodox Jews.