One of the president’s favorite rhetorical tricks is to place himself at the center of any debate and to banish his critics to the extreme fringes.

It was a technique he perfected during the 2008 campaign. For example: “At various stages in the campaign, some commentators have deemed me either ‘too black’ or ‘not black enough,’” Obama said during his speech on race relations in March of that year. In this way, the president frames himself as a centrist and all others as irrational and hopelessly partisan.

On the right, this technique has evolved into a running gag. “Some say that we should lob a volley of nuclear weapons at Iran tomorrow while others insist that we unilaterally normalize relations and formally apologize for the overthrow of Mossadeq. I reject this false choice.” Of course, no one is suggesting either of these extreme positions, but Obama has bravely cast them aside in favor of his eminently reasonable approach.

It is a cynical ploy, and it’s wearing thin. Even among Democrats.

Obama might have no sharper critic on the issue of Iranian nuclear negotiations than fellow Democrat, Sen. Bob Menendez (D-NJ). Today, Menendez accused the White House of adopting a position on new sanctions against the Iranian regime that aligns perfectly with the propagandist rhetoric coming out of Tehran.

The schism between Menendez and Obama has roots in a more personal gripe, apparently. According to CNN, Obama deployed his old rhetorical trick against Menendez during a Democratic retreat in Baltimore. There, the president implied that his approach to Iran was noble and virtuous and all others who disagree, including Menendez, are bought and paid for by special interests.

Menendez wasn’t having any of it.

The unusually sharp exchange, between a senior senator and a president from his own party, occurred during a Senate Democratic retreat at a hotel in Baltimore. A senior administration official also confirmed details of the exchange, which was first reported by the New York Times.

Obama said that as a former senator himself, he understood how outside forces — like special interests and donors — can influence senators to act, one of the senators recounted.

That’s when Menendez stood up to challenge the President, telling Obama he took “personal offense” to his assertions, the New York Times reported, arguing that he has worked to curb Iran’s nuclear ambitions for many years and was not motivated by political considerations.

Every Democrat that CNN spoke to about this incident downplayed the confrontational nature of this exchange, but it speaks for itself. It looks like Obama’s preferred oratorical maneuver is losing its luster.