Musk Wants $2 Trillion Cut From US Budget. That Would Be Tough.

Elon Musk predicted he could cut at least $2 trillion from the US federal budget, a lofty goal that would require a level of austerity unprecedented since the winding down of World War II.

His target, mentioned at Donald Trump’s Sunday rally in Madison Square Garden, exceeds the amount Congress spends annually on government agency operations, including defense. It would likely require making significant cuts to popular entitlement programs such as Social Security, Medicare, Medicaid and veterans’ benefits.

Elon Musk speaks at a Trump campaign event at Madison Square Garden in New York on Oct. 27.

Photographer: Adam Gray/Bloomberg

In short, it’s easier said than done — even for the world’s richest man, who Trump has said he’d appoint ...