Elon Musk on Sunday gave a brief speech at a campaign rally for Donald Trump in New York in which he said he'd save the US $2 trillion through a department of government efficiency.ANGELA WEISS/AFP via Getty ImagesElon Musk on Sunday briefly spoke at a campaign rally for Donald Trump in New York.In his speech, Musk said he'd save the US $2 trillion through a department of government efficiency.Musk and Trump have both suggested that Musk could be a member of Trump's cabinet if he's reelected.Elon Musk on Sunday gave a brief speech during a New York campaign rally for former President Donald Trump, in which the Tesla CEO said he'd save the United States $2 trillion in tax spending through a department of government efficiency.While introducing Musk, Howard Lutnick, the CEO of the financial services company Cantor Fitzgerald, described the SpaceX CEO as the "greatest capitalist in the history of the United States of America." As he took the stage, Lutnick asked Musk, "How much do you think we can rip out of this wasted $6.5 trillion Harris-Biden budget?""I think we can do at least $2 trillion," Musk replied, receiving cheers from the crowd.