If Cruz is rejected from the debates or should lose the primary then he absolutely should start a 3rd Party, because if Cruz loses the Primary it will be Bush, at that point we all will need a candidate and a Party to vote for, we need an opposition Party to the RepubliCrat uniparty. I think Cruz is bold enough to do that with some encouragement from "We The People", I think the numbers would be astounding breaking the morale of the Uniparty aka The Enemy Within and send them into panic mode greatly exposing their phony one party system.
Then we can see that the Republicans and Democrats are NOT to big to fail...
They could bring these traitors to heel quite simply by withdrawing from the party enough members to put Boehner and Mitch into minority status, then they could have real power. They won't but they could.