Also, I have no idea how much of that budget is actually spent usefully (coastal pollution watch by the Navy, gendarmerie, etc).

But we all know the global military budget is very high and massively fed by the US's own budget.

And faster than Jérôme can say "data is not the plural of anecdote" :-) let me tell you about my own valiant experience in the military.

It was 15 years ago but I know things haven't changed that much.  I did military service in a military administration where all military personnel from NCO on up had a civilian "double" who held the same job with an equivalent civilian rank.  The military were overstaffed and underworked by any standards meaning that their civilian doubles did practically no work at all.  This left plenty of time for the civilians to study tasks they would never perform.  Once they had passed the test proving they had acquired new skills, they were entitled to a pay raise of course.  The General in charge tried to change things by granting the pay raises to those who actually used the new skills in their job.  Silly general! He almost caused a strike before backing down from his new fascist rule.

I'm not claiming that all administrations are as wasteful as the military but I'm pretty sure we can lop off much gvt spending without crippling real public services.

Cheers