All 3 Uses of

fortify
in
Killing Kennedy

The fifty-one-year-old LBJ, as he is known, was perhaps the most successful and powerful Senate majority leader in U.S. history, adept at building partnerships and fortifying his party faithful to pass important legislation.†
p. 53.8

Thus fortified, Jackie nervously broached the subject to JFK over dinner one night.†
p. 68.9 *

fortified = to make stronger

The president fortified its rigidity this morning by wrapping the brace and his thighs in a thick layer of Ace bandages.†
p. 267.9

Definition:

to make stronger

in various senses, including:

to add defensive fortifications to a site to withstand attack -- as in "fortify the camp"
to make a structure or organization stronger -- as in "fortify the wall"
to inspire emotional and mental strength -- as in "fortify her spirits"
to strengthen an argument -- as in "fortify our argument"
to add nutrients to increase the healthfulness -- as in "bread fortified with folic acid and iron"
to add alcohol to make a drink stronger and/or less prone to spoiling -- as in "port, sherry, madeira, and other fortified wines"