The most likely nominees of the two parties are Trump and Clinton. Both are viewed by the electorate as untrustworthy and dishonest, probably accurately so.
Both lie with great fluency and élan, both have semi-shady pasts and questionable associates, both are a major turn-off for around half of the voters. Actually, it's probably different halves.
Assuming one of the two is elected in November, he or she will have difficulty governing, maybe even difficulty in attracting an audience to speeches in office. It is tempting to argue that our political process is broken, using them as exhibits A and B in our proof.
