Cecil, W5DXP wrote:
"The superposed forward voltage and reflected voltage can damage an
unprotected transmitter."

To do so, they would be in-phase and not out-of-phase. Entirely possible
if the transmission line is the right length.

If the reflected volts are in the same phase as the newly munted volts,
which are larger? With a reflection coefficient of 1, and a lossless
line, the open-circuit value of transmitter volts would face some lower
value of line volts on opposite ends of the internal impedance of the
transmitter. Which way does the current flow?

Theory is that it flows from the higher to the lower. That is, from the
transmitter to the line.

Best regards, Richard Harrison, KB5WZI