I may not have stated my thoughts as clearly as I intended.

The "claim" made by CMG is not a "claim."  It is a legal right which has
been transferred to them by the holders of the original rights.  This, at
least, is my understanding.

Trademark law is, I assume, the legitimate basis for their right. Although
I'm not an intellectual property or trademark attorney by any means, it
seems clear to me that a trademark is an entity unto itself:  assignable,
transferable, and different, in many respects, from a copyright.

Let's assume this scenario, for the sake of argument:

Mark Twain trademarks his name and persona while still alive.  The
application for trademark is accepted.  He then "owns" all the rights
thereunto appertaining, as they say.  Upon his death, those rights are part
of his estate, controlled and administered under the terms of his will by
the Mark Twain Foundation, directed by the law firm of Chamberlain, Willi,
and Ouchterloney, his attorneys.

By way of Clara's estate, or the continuing legal authority of the Mark
Twain
Foundation to exercise control over his name and persona, those "rights"
have devolved over time to CMG.  It seems that there is a valid distinction
between  copyright and trademark.  One may quote all day long until blue in
the face  from Twain, publish your own edition of Tom Sawyer, and never be
beholden to pay a dime. But,... If you wanted to endorse a particular brand
of scotch whiskey, or a particular fountain pen, or a particular brand of
cigar, and do so as "Mark Twain," using his likeness and persona, then some
arrangement with the interests that own and control those rights must be
made.  Otherwise, one would be in violation of trademark law and subject to
action by the owners of the rights.

Again, I'm not an attorney. If someone painted a picture of Mark  Twain and
used it in a commercial endeavor, who knows?  That may not violate
trademark. If, in a satirical piece, the Twain character was used, vilified,
sanctified, deified, or otherwise maligned, that may also be just fine.

But I do believe that fairly solid ground underlies the provenance of the
rights that CMG owns, or represents, on behalf of the Mark Twain Foundation.

Also, I recommend for further study this link from UC Berkeley's web page:

_http://bancroft.berkeley.edu/MTP/access.html_
(http://bancroft.berkeley.edu/MTP/access.html)

More specifically, this section, as regards  printed material:  (bold,
underline, and italics are mine)

"All valid copyrights on Mark Twain's words are held by Richard A. Watson
and JPMorgan Chase Bank as Trustees of the Mark Twain Foundation, which
reserves all reproduction or dramatization rights in every  medium. To write
to the Mark Twain Foundation, address your request to:

Richard A. Watson
Chamberlain, Willi, Ouchterloney, & Watson
575 Eighth Avenue, 16th Floor
New York, NY 10018

I hope this either helps to clarify my original post, or leads to further
discussion that can ascertain the true facts, if what I submit as my
understanding of them is wrong.

Roger Durrett
Charlotte, NC