House Democrats have asked the secretary of state, Marco Rubio , to publicly announce that Israel possesses nuclear weapons, arguing that Washington must end decades of ambiguity over the issue amid the conflict with Iran. In a letter sent on Monday, 30 Democrats wrote that it was unsustainable for Donald Trump to collaborate with the Israeli prime minister, Benjamin Netanyahu , on a military campaign against Iran – with the stated goal of preventing the country from obtaining a nuclear weapon – without publicly acknowledging the US ally’s possession of the bomb. “We are, in the fullest sense, fighting this war side by side with a country whose potential nuclear weapons program the United States government officially refuses to acknowledge,” reads the letter, which was led by the Texas Democrat Joaquin Castro.…