What's an acceptable expenses:operations ratio for nonprofits supporting the military?

80% / 20% should only be used as a guide. I'd love to see past violations as well as well as complaints or investigation past and ongoing included. As well as if any "rumors" have been vetted as false. Education is the key!  

It goes without saying that both good and bad (yes, even on the CFC) charities exist. Take the time to do your due diligence by researching the charities that interest you. Should you choose to donate, remember to assist only those charities of which 80% or greater of the monies go directly to supporting the said cause. Personal plug...One can never go wrong by investing in our youth.

If an organization is a legitimate 501c3 it's Form 990 (provides financial data) should be readily available.  Non-profits are required to file it to maintain their status.  As to your question--I have been told by someone that has worked in the industry for a long while that an 80/20 ratio or better is the "gold standard".  Having worked in non-profit for almost two years now, it should not be the only measure, and maybe not even your first.  What is more important, and is difficult to express objectively is the impact or effect the organization is having on its constituents.  The ratio, senior officer salary, etc. may be important indicators, but the big questions should be:  Is this organization effectively fulfilling its stated mission?  Are they making efforts to objectively illustrate it?  Not just using anecdotal success stories and emotional testimonials.  I could go on about this and efforts of some organizations to provide measures--such as non-profits claiming medical rehabilitative benefit, etc.