This Is How Robert Mueller Can Force Trump to Testify

"Despite a global brand as a reckless Twitter addict and loudmouth, Donald Trump has a history of behaving himself in formal legal settings. Before he was president, the real estate heir was deposed dozens of times, mostly in various lawsuits related to his businesses, which have been accused of discriminating against black people, screwing over renters, and stiffing contractors. When pressed to tell the truth under penalty of perjury in formal depositions, Trump has tended to provide something resembling it. "

https://www.vice.com/en_us/article/kzpamy/how-robert-mueller-can-force-trump-to-testify