I think Cornyn could lose this race very easily... he was out talking about how Texans don’t want fences just 3 weeks ago... he is arrogant and out of touch with his base... which won’t help him this time around.
Even if the tightness of the Cruz win was not indicative of what will happen in 2020, Texas’s will be a battleground state soon. Then any kind of Republican - conservative, moderate, Trump, Bush - will struggle to win in Texas.
Demographics is destiny...eventually.