The implication of the remark, as President Trump says, “a better security” venue, is that something of much greater significance than traditional White House operations is in need of attention. To such a degree, that prior strategic discussion arrangements are not considered “secure enough.”

President Trump does not like Camp David.

Before taking office, President Trump once told a German journalist in an interview, “Camp David is very rustic, it’s nice, you’d like it. You know how long you’d like it? For about 30 minutes.”

So, the big picture questions become:

What issue would be of such importance, that changing the venue would be needed in order to address it?

What issue(s) has DC interests so aligned, that Rubio and Trump are two of a very small group on the other side of it?