Joe Biden could be axed as the Democrat candidate as late as August amid growing concerns for his mental fitness. As the latest polls remain tight, senior democrats suggest they will delay their strike as late as possible to slam hopes of a second term. The formal nomination is set to take place in Chicago on August 19. Democrat operatives in Washington DC say the late hit will not only stop Biden from becoming president again but also aims to maximise the Democrats’ chances of keeping control of the Senate in November, The Sun reports. Biden’s mental fitness has been questioned following the …