Since Kamala Harris became his opponent in the race for US president, Donald Trump has argued that she is responsible for a migrant crisis. He says President Joe Biden named her the ‘border czar’, in charge of dealing with the unprecedented number of people attempting to cross the US-Mexico border. It’s a policy area that the Trump campaign hopes will win him the election in November. So what’s real, and what’s fake, when it comes to Kamala Harris and the US border?