Of all of Shakespeare’s turns of phrase, “a pound of flesh” is perhaps the one that has taken the most wrong turns. Indeed, it has ubiquitously, and unfortunately, become a “Jeopardy” answer. Yet, all that most people remember about “The Merchant of Venice” is the canard of an implacable Jew thirsting for Christian blood.

The double bill of Elizabethan anti-Semitism now running at the Duke Theater, featuring Shakespeare’s “The Merchant of Venice” and Christopher Marlowe’s, “The Jew of Malta,” performed in rotating repertory by the Theater for a New Audience, while accomplished, doesn’t quite achieve the loftier aspirations either Shakespeare or Marlowe may have intended.

The received wisdom on Shakespeare and his creation of Shylock has been that it wasn’t he who had a Jew problem. It was the British who hated Jews; the Bard merely conceived of a Jewish character who would appeal to the masses.

Smarter audiences, however, were able to detect the deeper meaning behind Shylock’s insistence on a pound of flesh as a remedy for his dispute with Antonio, the merchant of Venice.

So while groundlings in the pit of the Globe Theatre cheered as Shylock, in all his villainy and vilification, got what he deserved, more sensitive souls, came away wondering whether Portia would have been better off marrying the principled Shylock rather than the superficial Italian lout who so casually gave away her wedding ring.

The two current stylish productions play to the masses and dispense with the moral lessons. Shylock and Barabas, Malta’s detested Jew in Marlowe’s play, are straight out of central casting — poster boys for Jewish caricature and stereotype, moneyed and monstrous, and, of course, unsympathetic and unlovable. Both are portrayed by the actor, F. Murray Abraham, who gives two convincing performances: one of submissive restraint for Shylock, and the other of charismatic bravado for Barabas.

Yet, Mr. Abraham’s talent is ultimately squandered in these two productions that never aim for anything higher than the easy laugh or the simple insight. Abraham deftly alternates between two cardboard figures — punch-me dolls of righteously deserved anti-Semitism. While Shylock and Barabas, most assuredly, call for two different kinds of performances, there is a wide range of emotion and complexity in between them that goes completely unexplored. Instead, “Merchant” and “Malta” capitulate to all the lowbrow presumptions of each play — Jew as bad guy; Jew who must not survive the final curtain — without embracing the delicate balance of honest and thoughtful reflection the playwrights intended to impart with the more urgent message of prejudice as poison.

After all, Shylock and Barabas are actually the true protagonists of each play, victims of unremitting hatred who, paradoxically, are asked to be merciful and cooperative.

But those object lessons are lost in these productions. The complicated back-stories and inner worlds never make it in front of the footlights. The audience has no idea why Jessica hates her father, Shylock, so much; nor does it know why Abigail loves her father, Barabas, in kind. We just know that they do, and whatever the reasons for their daughterly designs, we are quite certain that, when each daughter ultimately betrays her father, it’s a fine day in Venice and Malta.

One source of moral deflection is the updated, high-tech setting where Shylock seeks his revenge. Gone is the original ghetto and the majestic Rialto; in their place is a sleek, urban Wall Street, without the gondolas but replete with iMacs and digital cameras. While cute, these gadgets only distance and desensitize the humanity of the play even further. The only thing Italian about this Venice is the suits and shoes Antonio and friends so elegantly and fittingly wear.

Indeed, even Shylock is costumed less like a moneylender and more like a man who runs a hedge fund. When Tubal communicates with Shylock via a Bluetooth device during what is supposed to be the most poignant scene in the play — when Shylock learns that Jessica, in a night of debauched partying, trades her mother’s wedding ring for a monkey — the message has been sent that the play is far more interested in the laugh than the longing.

There is courage in mounting these artifacts of animus back to back. Perhaps there are no groundlings in Gotham, and so the risk of missing the message is not as great. Surely we already know the moral consequences of hate and the ungovernable force of nature that revenge can become.

And then again, maybe not.

Mr. Rosenbaum is a novelist, essayist, and law professor, and the author of “The Golems of Gotham.”