Right. And it's also true that Trump has made many deceptive or untruthful statements about his own past and record.
But my point is that if all Trump and Cruz (and their supporters) do is stand there and call each other liars, then there is a great risk that everyone else (people who support other GOP candidates, as well as right-leaning independents who would be vital to a general election win) will walk away with the image that BOTH of them are liars who are not worth supporting. In that case, then say hello to President Rubio (or, worse, President Clinton II)
Well, point them out.