This is a shot in the dark; I don't know if the quotation exists, but
I rather expect that someone somewhere has expressed a thought that
has occurred to me, namely:

When a generation of national leaders comes into power who no longer
remember war firsthand, the risk increases that they will start one.

The quotation sought could express this from any viewpoint:  an
aphorism of warning; an historian's remark about a specific event; a
retiring politician's farewell address; etc.  - from any era or part
of the world -  perhaps indirectly relative to an analysis of how a
war has occurred that was not intended to become such.

I don't need examples of the latter  - just the appropriate quotation
about the leaders.  However, suggestions of such examples might help
joggle someone else to recall a source for such a statement.  It would
be nice if the quotation predated the obvious examples of the last
20-30 years and was a pithy as possible.

I haven't set a very high price, because I expect that an answer will
result from a Researcher's personal knowledge rather than from
extensive web searching.  But if that brings the result, it will be
honored, also if it follows a lead by a commenter.
Comments are very welcome.

Thank you and good luck.

Myoarin,

Thanks for accepting my suggestion as your official answer!

For the record, here's the quote, from George McGovern:

"It has always seemed to me that the leaders who are the quickest to
send our boys and our young to war are those who have never known war
themselves."

Democratic Veteran
http://www.usndemvet.com/blog/archives/2004_02.html

Sometimes I wish I could dazzle folks with my brilliant search
strategies. But brilliance seldom has anything to do with it. After
several hours of failed searches, I came across this quote with the
use of a Google search string designed to find another quote, one that
I thought was by Fidel Castro:

Google Web Search: castro "those who have never * war
://www.google.com/search?hl=en&q=castro+%22those+who+have+never+*+war

The Castro quote that I was looking for this one:

"Only those who have never experienced war truly crave it."

Blue Lemur Forums
http://forums.bluelemur.com/viewtopic.php?t=4516&

After I had found the McGovern quote, I went back to the Blue Lemur
Forums. Upon re-reading the post in which the "Castro" quote appeared,
I discovered that the quote is actually the poster's sig file which
appears at the bottom of all his posts, and the mention of Fidel
Castro is apparently unrelated!

I'm not sure whether this roundabout, mistake-driven search technique
is of any use to others, but that's the way it happened. I began by
looking for a quote that probably has no association with the person I
thought said it, and while I was on that wild goose chase, another
goose flew by!

Best,
Pink

Pink,
Thank you for your persistance and success.  Castro was also somewhat
on target, but would not have been as appropriate a source, although
there is no reason for his not expressing a similar sentiment.  I am
pleased that it was you who found the so loosely defined quotation I
was just assuming someone important might have made.  The tip is more
than I had "budgeted" but very well deserved and also in appreciation
for your always delightful and savvy postings.  :)
Thank you, Myo

Is this any help?
"Those Who Forget History Are Doomed to Repeat It"
See: http://answers.google.com/answers/threadview?id=495329

Ponder,
Yes, that is certainly related, but I am hoping someone will find "the
quotation" that is closer to my idea, that I have sometimes expressed
differently from in the question:  along the line:  war is like
measles; once you have survived it, you don't catch it again.

Thanks, Myoarin

How's this ...

When the Dogs of War are howling nobody hears the Doves of Peace.

I made that up all by myself in June 2006.

How about "To not know what war is, invites the danger of it"

Very good, Bryan, but that doesn't emphasize my point about the
younger generation's being more susceptible to "catching" war.  Try
again.  Maybe I can quote you:  "As the noted author Bryan of Hove
once remarked:  '....'."

Thx1138 is definitely on the right path, and the quotation is very
pithy, almost too much so.  I am hoping someone said/wrote something
so close to what I want that I don't have to explain my application of
it (in a letter to the editors that should make some politicians pale 
:).

Of course, the quotation does not have to orginally have been English.

Thanks to you both.
Myo

How about this, from George McGovern?

"It has always seemed to me that the leaders who are the quickest to
send our boys and our young to war are those who have never known war
themselves."

http://www.usndemvet.com/blog/archives/2004_02.html

Or this, from John Bomar?

"For, most assuredly, those who have never smelled or tasted war rush
quickest to its rotting banquet, and stay longest at the feast."

http://www.worldproutassembly.org/archives/2006/03/

Wow, Pinkfreud, respect!  John Bomar is a bit too dramatic, and not
such a good source for my purpose, but George McGovern hit the nail on
the head.  Kinda nice to find that a nice guy thinks like I do.

Please post an answer and reveal how you found the quotation.

Regards, Myo

Further suggestions are still welcome.

Wow, Myoarin, thanks for the five stars, the kind words, and the
eye-popping tip! I sure wish that searching for the wrong thing worked
out this well every time! :-)

~Pink

Pink,
It's my pleasure, enjoy!  
Regards, Myo

Not relevant, but amusing :

Young bankers succeed older bankers, and repeat their mistakes

Frde,
In principle, quite relevant, and we've seen it over and over again,
especially on lending to foreign countries.  Bankers are herd animals.
No doubt you know the old saw about how to get ahead in banking:  make
loans with a repayment period that goes beyond your next expected
promotion date.
Cheers, Myo

One thing I worked out for myself, then got confirmed by a senior banker

- when a bank is hurting, it doesn't bleat

I think that this extends to sensibly run economies
- we heard little about the Ost absorbtion problems until Grosser
Deutschland was well stable.