After a technical snafu that required two wireless microphones before it was sorted out, Netanyahu revealed his first slide in a dramatic multimedia presentation, displayed on a screen that dwarfed the Israeli leader.
An image of an Iranian flag and a nuclear symbol framed the title page: "Atomic Archive: Iran's Secret Nuclear Files."
Moments later, as Netanyahu worked through video clips from Iranian leaders, two words popped up on screen in letters that were half as tall as the Prime Minister: "Iran lied."
Netanyahu's show -- and it was a show, broadcast live in prime-time and carried on CNN and other American cable networks -- was in full swing.
"Tonight, we are going to reveal new and conclusive proof of the secret nuclear weapons program that Iran has been hiding for years from the international community in its secret atomic archive."
The Prime Minister, wearing a dark suit, white shirt and light blue tie, walked over to two large display cases on stage and pulled down the black sheets that hid their contents.
This was Netanyahu's mother lode. This is what he wanted to show the world.
A wall of gleaming CDs containing 55,000 files purportedly from Iran's nuclear archive? Check.
A cabinet of color-coded binders with another 55,000 pages allegedly from the same archive? Got that, too.
New evidence that Iran violated the nuclear agreement known as the Joint Comprehensive Plan of Action, or JCPOA? Not so fast.
Nonproliferation experts who spoke with CNN say Netanyahu provided no evidence that Iran contravened the terms of the agreement. Moreover, they say there was nothing new in Netanyahu's speech. And the other signatories to the JCPOA, with the notable exception of America, agree with that assessment.
"There's nothing new in the material that Netanyahu revealed yesterday. All of it was information that the International Atomic Energy Agency (IAEA) already had and has already commented on," said Mark Fitzpatrick, executive director of the International Institute for Strategic Studies and an expert on nonproliferation.
Echoing Fitzpatrick is Jeffrey Lewis, another nonproliferation expert and scholar at the Middlebury Institute of International Studies. "Everything Netanyahu said from the name of that [Iranian nuclear development] plan down to the fine details was described in the IAEA's final report about Iran's nuclear weapons program, so there was nothing new about the scope of that program."
Both experts agreed on the most surprising element of Netanyahu's presentation -- that Israel had managed to acquire what appeared to be a large portion of Iran's nuclear archive in what Netanyahu called one of the country's greatest "intelligence achievements." US Secretary of State Mike Pompeo endorsed the authenticity of the materials.
"The documents show that Iran had a secret nuclear weapons program for years. Iran sought to develop nuclear weapons and missile delivery systems. Iran hid a vast atomic archive from the world and from the IAEA — until today," said Pompeo in a statement after the speech.
But that doesn't mean the materials revealed a trove of new information, though both Fitzpatrick and Lewis caution that such a large cache of documents will take time to properly analyze.
As for what Netanyahu highlighted in his presentation? "All of these documents are of a historical nature dating back to before 2003," said Lewis.
The IAEA, which is the UN's nuclear watchdog tasked with inspections and monitoring of Iran's nuclear program, agreed.
"Before the end of 2003, an organizational structure was in place in Iran suitable for the coordination of a range of activities relevant to the development of a nuclear explosive device," said IAEA spokesman Fredrik Dahl. "Although some activities took place after 2003, they were not part of a coordinated effort."
There are "no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," he said. He concluded that Iran's activities "did not advance beyond feasibility and scientific studies, and the acquisition of certain relevant technical competences and capabilities."
The IAEA was aware of most, if not all the documents Netanyahu highlighted, as Fitzpatrick and Lewis point out. Some were included in a series of IAEA reports leading up to the Iran nuclear deal.
World leaders -- again, with the exception of the Trump administration -- were similarly not impressed.
EU Foreign Affairs High Representative Federica Mogherini said, "I have not seen from Prime Minister Netanyahu arguments for the moment on noncompliance, meaning violation by Iran of its nuclear commitments under the [nuclear] deal."
Russia stood by the current deal, rejecting any push to update or change the JCPOA. France, Germany, and the United Kingdom said Netanyahu's presentation was exactly a case for keeping the deal in place, because it provided for inspection and monitoring of Iran's nuclear program and, if needed, sanctions.
And what about one of the central accusations of Netanyahu's presentation, that Iran lied? It was a talking point he hit over and over, making for easy sound bites and compelling television.
Well, that didn't surprise anyone either.
"Everybody knew that they lied. There's nothing new about that," Lewis said flatly.
"The Iranians had a nuclear weapons program. We knew this," agreed Fitzpatrick.
Lewis added: "We already knew the outlines of the [Iranian nuclear] program in great detail, and all this did was color it in, sometimes in pornographic detail."
As Mogherini and others pointed out, Netanyahu didn't establish a solid case that Iran had violated the terms of the nuclear agreement, nor did he present evidence to that effect, despite Netanyahu saying Iran didn't come clean about their previous nuclear work. Though world leaders agreed the IAEA needed to analyze all the documents and files uncovered, there was no suggestion that what was revealed so far mandated a renewed imposition of sanctions against Tehran.
Instead, Netanyahu suggested that Iran's holding of the knowledge from when they had worked on development of nuclear weapons nearly two decades ago was proof enough that they would one day return to their work. On this point, Netanyahu cited Iran's repeated calls for the destruction of the United States and Israel, as well as Iran's ballistic missile program, which was not included as a part of the JCPOA.
Fitzpatrick is skeptical.
"The argument is posed in a way that ascribes motives that we don't know. It's been clear for many years that Iran had a nuclear hedging strategy, and that they have long wanted an option to produce a nuclear weapon. When they agreed to the [nuclear] deal in 2015, they postponed any day in which they would be able to pursue that option, but they never gave up the option. That's why Israel has never liked this deal -- because Iran has a nuclear hedging strategy."
Correction: This article was amended to correct a misattributed quote.