xargs - how to get it to execute input args as "the command"?

[Linda A. Walsh]

I would have thought this to be the easiest case, Instead of reading
in a line to use as an argument, or something to merge with a command,
how can I get xargs just to execute the line read in as the command?

I would have thought giving it -n1 -P12 and nothing else would have
executed up to 12 procs at a time, 1 line being used as the 'proc'.

But it doesn't seem to like that.

Also, how can I tell it to use 1 line at a time but not consider double quotes
to be special?   It says to use -0 to not have double quotes considered special,
but then it doesn't break at the linefeed.  Um... Why can't it do it's job of
reading in 1 cmdline args / line and exec whatever it has read in?

FWIW, I don't want the extra overhead of spawning a shell with each command
as there are ~ 80+K lines I want to execute...

How do I get xargs to do this?

Thanks!