>perl -wMstrict -le
"print '------ output ------';
 my $s = shift;
 print $s;
 my @chunks = split / AND /, $s;
 @chunks = map { /OR/ ? qq{($_)} : $_ } @chunks;
 print join ' AND ', @chunks;
"
"huckabee AND jfkadlsfj fdsfldfj06329 OR reagan AND OReilly AND clinton OR sebelius OR mccain"
------ output ------
huckabee AND jfkadlsfj fdsfldfj06329 OR reagan AND OReilly AND clinton OR sebelius OR mccain
huckabee AND (jfkadlsfj fdsfldfj06329 OR reagan) AND (OReilly) AND (clinton OR sebelius OR mccain)