“A veteran - whether active duty, retired, national guard, or reserve - is someone who, at one point in his or her life, wrote a blank check made payable to The ‘United States of America’, for an amount of ‘up to and including my life.’”
(Seems to me a blank check has no amount on it, but that’s besides the point.)
I’ve seen this quote in a number of places, always attributed to “Author unknown.” Anyone know when and wear it started?
That IS the point - a blank, signed check can have the amount written in by the person who cashes it. Of course, it can only be cashed up to the amount in the signer’s bank account - but in the metaphorical case in the OP’s quote, it can include the person’s life.