Donald Trump’s campaign, reeling Sunday after a report that the business mogul may not have paid taxes for as many as 18 years after declaring a $916 million loss on his 1995 returns, mounted a vigorous defense by calling the revelation proof of the Republican presidential nominee’s “genius.” Former New York mayor Rudy Giuliani and New Jersey Gov. Chris Christie, Trump’s leading surrogates, fanned out across the Sunday political talk shows to defend their candidate — but they did not dispute the Times’s findings, nor has Trump’s campaign. “He’s a genius — absolute genius,” Giuliani said on ABC’s “This Week.” “This was a perfectly legal application of the tax code, and he would’ve been a fool not to take advantage of it.”