John McCain will sit this one out.
The man who first gave Sarah Palin a starring national role in August 2008 will try to avoid getting involved in the Trump endorsement storyline -- for now, at least.
"Senator McCain has great respect and appreciation for Governor Palin," a senior aide told NBC News. "As he has said since Senator [Lindsey] Graham exited the race, he will not be taking sides and endorsing a primary candidate at this point in the race."
McCain has been publicly supportive of Palin through all the attention and controversy in recent years but they keep some distance. He still credits her with exciting the conservative base and boosting fundraising for their White House bid.
Palin campaigned for McCain's 2010 Senate re-election and has done her part to blunt conservative attacks against him even though they moved on to different paths within the Republican Party.
See more of Palin's endorsement of Trump:
Another dimension of Palin choosing Trump over Ted Cruz is that McCain has tangled so publicly and sometimes personally with the Texas senator.
While McCain says he has a "cordial" relationship with Cruz, had Palin endorsed him that could have been interpreted as a slap to McCain.
Of course, Trump mocked McCain's war record in Iowa last summer and Palin stepped around that.