Is there a clue here?

Anybody in doubt about how exactly the National Security aspect of the EU referendum argues out might like to think of this for a moment or two, and how the two gentlemen above might see it.

Vladimir Putin, President of Russia would love to see a brexit vote.  Well he would wouldn't he?  The way Russia sees it, the EU has taken its territory. Lithuania, Latvia and Estonia were, within living memory, Soviet Socialist Republics directly making up part of the USSR.  Other, “Iron Curtain” countries are now EU member states.  Brexit for him would mean weakened EU, weakened NATO, so more power and influence for Russia.

Barack Obama, current president of the USA (at the time of our referendum anyway, whoever gets the job next) – hopes we remain IN.  I think it's fair to say that, for many people on both sides of the Atlantic we think of each other as our favourite ally.  Or favorite ally (see what I did there?!) So it's no surprise that the Leave campaign are asking him to keep quiet and, as they say, “stop interfering”.  For the president of the biggest country in NATO, warning his allies not to give Comrade Putin the handsome present of a weakened Western alliance is not interfering; I'd say it's a rather vital part of his job.