A Physics Question

I want, at least want, causality to be part of the theory of time travel.  I do not want to consider the alternative, however right it might be.

If causality is real, and we can't go back and support Adolph as an art student, preventing his move into politics, does that mean all "time travel" is impossible?  I think not.

Perhaps the real question is "Will we ever meet aliens smarter than ourselves or not?" and I don't think the rational answer is "Awesome the bestestest!" Claims by the current leadership of the United States of America notwithstanding.

Anyway. Perhaps it is possible that causality prevents time travel, that does not prevent time viewing.  Time Viewing could use information available in the current time to deduce what things were like earlier, and display them.   Perhaps nothing meaningful, more likely nothing meaningful, will come of this viewing, except in a few instances, for example, the Kennedy and King assassinations.