Considering the turmoil in America 1966-71
IOTL, lord knows I don't find this senario ASB @ all. But I don't think it was very
likely. As his popularity plunged & protests
against him mounted(with hordes of anti-
war demonstrators chanting "Hey, hey LBJ
how many kids did you kill today?")Johnson
reacted by going out in public less & less.
When he did, he avoided motorcades &
shaking hands in favor of speeches indoors
where the crowds could be easily screened &
the exits & entrances closely watched by the
Secret Service. Under those circumstances
it would have been very difficult to shoot
Johnson(& in fact no assination attempts
were even made, though there were plenty
of threats).