If your rule is that ambitious, publicity-seeking politicians can likely be bought, then you have no basis for distinguishing among politicians. They are all ambitious, more so at higher levels, and they all seek publicity. Neither are in themselves bad qualities in someone running for elected office in a democratic system. Of course we sometimes see in them extremes of insincerity here, and you and I might honestly see Cruz or any other politician differently in that sense.
Your prior argument was that Cruz’s position on illegal immigration was not credible because he had given toys to children and a bill he wrote did not pass. Do you wish to maintain that position?
Not an answer to your question...but look at this..