This isn't a remarkable standard; being under investigation would be a disqualifier for any prospective VICE Presidential candidate, so why didn't this render Mrs. Clinton's PRESIDENTIAL campaign a non-starter?
Being a rapist, fascist, xenophobe who constantly flirts with Ku Klux Clan and conspiracy theorists and a none-tax-payer who's constantly broken the law by not paying his workers and contractors at all, while at the same time having broken the law big time both with his foundation (of which at least 90% of its income has gone into his own pockets) and Trump University, which has been proven to be not just one of the biggest pyramide schemes in the US' history, but anywhere in the world - all of this is normally multiple times excluding from anyone even coming near the nomination of a major party. So how on earth do you defend that?