This is a really great, in-depth piece by Armin Rosen on how AIPAC exercises influence in Washington -- and the limits of said influence. While many people think of AIPAC as this towering, 900 lbs monster which makes and destroys political careers, the organization actually has a very different mode of operation. It builds relationships. It makes sure that, whoever is in office of whichever party, they have a route to that person's office so that they can make their concerns known.
While this has been obviously effective, Rosen contends that the Iran Deal case shows the limits of the strategy. Because AIPAC is exceptionally cautious about building and maintaining relationships, it cannot and does not threaten any serious consequences for Congresspersons who flout their will. Representatives were willing to buck AIPAC because they knew AIPAC wasn't going to cut them loose for the apostasy. And that, in turn, has made certain other (generally rightward) forces on the "pro-Israel" community think that AIPAC's lost its edge. What good is it being the proverbially unstoppable "Israel Lobby" if you get stopped on the one issue you actually throw your entire weight behind?
There's a degree to which that's true, though I think Rosen understates the benefits of AIPAC's relationship model even in the wake of the Iran Deal. It's almost certainly true that AIPAC's model is ill-suited to a drawn out fight where a powerful political figure, like the President, digs in his heels and directly contravenes a core AIPAC policy objective. But there will inevitably be very few cases like that, because when it comes to foreign policy -- even Israel-related foreign policy -- it will not be that often that major political figures will have independent preferences strong enough to prompt such a knockdown fight. Where AIPAC's model shines is in greasing the path for the mundane, everyday bits of legislation and funding that only a very few people care about. In those circumstances, relationships and access rule the roost, and AIPAC works very, very well.
I'd also be curious as to Rosen's view on another of my hypothesis: that regarding the degree to which Jewish groups are comfortable publicly feuding with Democratic versus Republican politicians on Israel. Rosen observes that most of AIPAC's staff are Democrats (unsurprising -- it is a predominantly Jewish group, after all), and my argument has been that Jewish groups are willing to argue with Democratic politicians because they have the essential confidence that such arguments won't break the relationship entirely. They're "in the family", so to speak. Friends fight, but that doesn't mean they don't cease being friends. By contrast, there seems to be an implicit concern that any non-trivial attack on GOP policy initiatives by a Jewish group will see a swift and brutal excommunication by the Republicans. For a relationship-focused group like AIPAC, this is a harrowing proposition. Simply put, if the name of the game for AIPAC is relationships, then preserving Republican relationships requires a lot more hand-holding and obsequiousness compared to their more resilient Democratic counterparts (who can handle a tough period like the Iran negotiations and still come back to the table on matters of shared interest later on).