I did not see that coming. Although I should have. One of the aggravating things about Rick Santorum in 2012 was that I generally liked his foreign policy instincts; this would normally be a plus for a candidate, except that I kind of didn’t like Santorum’s demeanor generally. But I can see Santorum going with Rubio on natsec grounds.
PS: Yes, I can imagine that this news was distressing to some candidates out there.