President Barack Obama said on Tuesday that Donald Trump is 'unfit' for the presidency because he lacks 'basic knowledge' of world affairs and is 'woefully unprepared to do this job.' In an attack on the Republican nominee’s temperament and work ethic, Obama called on Republican leaders who have denounced some of Trump’s most inflammatory statements in recent days and weeks to cut ties with their party’s candidate. 'The question they have to ask themselves is if you are repeatedly having to say in very strong terms that what he has to say is unacceptable, why are you still endorsing him?' Obama asked. 'What does this say about your party that he is your standard bearer?'