NEW YORK – The energy at the Jerusalem Post Annual Conference in Manhattan on Sunday was palpable, with a crowd that didn’t hesitate to express itself.

It was exceedingly clear where much of the crowd stood, as it peppered the speeches, panels and interviews with cheering and occasional boos.

The hottest topics of the day focused on two capital cities: Jerusalem and Tehran.

Nothing was more certain to get a cheer from the crowd than US President Donald Trump’s plan to move the US Embassy from Tel Aviv to Jerusalem later this month – like when Ambassador to the UN Danny Danon said Trump is considering attending the opening ceremony for the new embassy.

And the same went for talking tough on Iran.

“Don’t test Prime Minister [Benjamin] Netanyahu,” Regional Cooperation Minister Tzachi Hanegbi warned Tehran, engendering applause.

Former IDF chief of staff Gabi Ashkenazi managed to combine two crowd-pleasing themes by commending Trump for wanting to get rid of the Iran nuclear deal.

Danon’s remarks about US Ambassador to the UN Nikki Haley got what may have been the strongest applause of the day, in keeping with recent polls showing that she is highly popular.

However, former prime minister Ehud Olmert’s remark that Jerusalem should be divided, with Arab villages on the capital’s periphery not remaining part of it, was met with tenuous applause.

When I interviewed Senator Ben Cardin – the senior US Senator from Maryland, the former ranking member of the Senate Foreign Relations Committee, and a Democrat – you could get whiplash from the crowd, cheering one minute and jeering the next.

Few could doubt Cardin’s pro-Israel bona fides in his decades of public service, but when he mentioned that he spoke at the J Street Conference, the crowd seemed to do just that, and began to jeer.

And they booed again when Cardin gave Congress credit for recognizing Jerusalem as Israel’s capital 23 years ago, as opposed to US President Donald Trump, who did so last year.

But when he talked about bipartisan cooperation, especially on legislation to stop boycotts of Israel, they cheered. There was a raucous round of applause for Cardin’s support for cracking down on Iran’s ballistic missiles and its growing foothold in Syria.

But it was off the stage, when I talked to attendees, that I learned what interested them the most. They liked the fact that Cardin was confronted with growing anti-Israel, pro-boycott sentiment in the fringes of his party. In response, he denied that these were strong forces in the Democratic Party, while still expressing concern that Israel was becoming “a partisan wedge issue.”

And when I mentioned to people that I’m currently on a speaking tour of US college campuses, many said to me, “Oh, you’re speaking about BDS.”

Well, no, I responded. I’m the Knesset reporter, so I’m speaking about Israeli politics.

But this says something about the preoccupations of the attendees. On stage, there were plenty of positive messages about Israeli innovations in technology and medicine, and Israel’s humanitarian work and growing economy.

Off stage, people were more worried about the threats facing Israel, whether against its physical security or its position in the public diplomacy arena.

The crowd spent the day cheering out loud and applauding Israel. But behind that exuberance lay an undercurrent of concern.