Trump has Cornyn in a box

i've watched Senator John Cornyn (R-TX) give speeches in recent days and it seems pretty clear that immigration reform is a big problem for him. Pres. Trump doesn't want to let more brown-skinned people in the country and has refused numerous bi-partisan legislative attempts with a stern "nyet". My guess is he won't allow ANY reform and that he intends to deport everyone he can. This is the problem for Sen. Cornyn. In his state they accept and even recognize the importance of immigrants. So, he's in a box. He wants something critical to his reelection and the president won't let him have it. He complains bitterly that the Democrats won't bend down and kiss the feet of Pres. Trump. Democrats have wanted to get this done since we had Pres. Obama in office, but Senate Republican Leader Mitch McConnell (R-KY) (then in the minority) always said "Nyet!"

Who is going to run for the senate in Texas for Democrats? It seems to me this is a moment where the Trump Effect has some Republicans stuck. There are probably others in border states where the voters want DACA Dreamers saved, but their senator can do nothing to help them because Pres. Trump is a racist. He's the leader of the Republican Party and that's the way it is.