WASHINGTON — Harvard Law professor and Israel advocate Alan Dershowitz took the stage at AIPAC’s annual policy conference Sunday to showcase a new Israeli technology that can seemingly create water out of thin air.

He touted the innovation, which could provide humanitarian aid to remote parts of a world in which two-thirds suffer from water scarcity, as an instrument to combat the Boycott, Divestment and Sanctions movement against Israel.

“There is no weapon more powerful in the fight against BDS than for Israel to develop technologies that the world cannot live without,” the BDS critic told the crowd of nearly 18,000. “You cannot boycott products that you can’t live without.”

Standing onstage inside the Washington Convention Center, Dershowitz and AIPAC National Managing Director Elliot Brandt unveiled the technology from the Israeli company Water Gen — a contraption that is able to pull water from the air and purify it.

The device, they said, can produce 15-20 liters of drinkable water a day without the environmental costs of bottled water.

They operated the device in the course of the presentation, which culminated with them drinking glasses of water which, they marveled, had been produced there and then from the air in the room.

Brandt noted Seth Siegel’s 2015 book “Let There Be Water: Israel’s Solution for a Water-Starved World,” which detailed the “Zionist dream to overcome water scarcity.”

“Let’s remember that Theodor Herzl talked about — the pioneers of Israel will be people who helped develop water,” Dershowitz amended. “And Yitzhak Rabin: originally he didn’t want to be a soldier, he wanted to be a water engineer.”

Roughly 1.2 billion people — almost one-fifth of the world’s population — live in areas of water scarcity, according to the United Nations Department of Economic and Social Affairs.

Dershowitz said the water-making innovation could be deployed to areas that lacked access to potable water.

He mentioned not only parts of the developing world like Haiti, but also New Orleans after Hurricane Katrina and Flint, Michigan during its most recent water crisis, in which drinking water was contaminated by high levels of lead.