Donald Trump is aggressive in court, but he tends to back down once you hit him back, according to the former president’s biographer, who beat a $5 billion lawsuit over financial allegations. Tim O’Brien, who spent massive amounts of time with Trump before writing TrumpNation: The Art of Being the Donald, appeared on MSNBC on Sunday to discuss Trump’s current legal affairs. The host noted that O’Brien was intimately familiar with Trump’s legal team, and asked for his thoughts on their strategies. The host said, “You have direct experience with the Trump legal team as a legal opponent. Trump su…