Donald Trump can truthfully call Ted Cruz a liar but there is no question that he is a much bigger liar. The difference is that he gets away with it because he has figured out that when you say something on TV, huge numbers of people hear it and assume it to be true. When fact-checkers later look into your claims and publish the truth, many fewer people (usually just those following politics closely) hear the refutations. So he wins.
Of course, all politicians know this basic fact and try to do it too. The difference with Trump is that he gets so much more coverage of anything he says than others that his ratio of lies heard to truth heard is much larger than that of others.
The Daily Show debunked the brazenly false claims Trump made in his victory speech on Tuesday night. But it will do little good.
(This clip aired on March 9, 2016. To get suggestions on how to view clips of The Daily Show and The Nightly Show outside the US, please see this earlier post. If the videos autoplay, please see here for a diagnosis and possible solutions.)