Compare Trump's reaction to Ted's tweet reaction to Palin's endorsement of Trump below:
"Ted Cruz @tedcruz I love @SarahPalinUSA Without her support, I wouldn't be in the Senate. Regardless of what she does in 2016, I will always be a big fan. 12:55 PM - 19 Jan 2016"
Cruz is thankful for Palins help in his winning a Senate seat. Palin did not support Cruz for the Presidency. In spite of this Cruz has a positive feeling about Palin. Trump has no such feeling regarding Walker. Walker has been very negative toward Trump since the debates. Could be that Walker is a sore loser and now has an opportunity to weaken Trump a bit.