Here's some more of the passage, which I found here
" He determined to become a good speaker and didn’t stop in that
determination until he became a world-respected economic consultant to the government. His name is Clarence B. Randall. In one of his thoughtful books, Freedom’s Faith, he has this to say about public speaking:
“I have service stripes all the way up one sleeve and all the way down the other from appearances before luncheons and dinners of manufacturers’ associations, Chambers of Commerce, Rotary Clubs, fundraising campaigns, alumni organizations and all the rest. I talked myself into World War I by a patriotic address in Escanaba, Michigan; I have barnstormed for charity with Mickey Rooney, and for education with President James Bryant Conant of Harvard and Chancellor Robert M. Hutchins of the University of Chicago; and I have even made an after-dinner speech in very bad French.”
“I think I know something about what an audience will listen to. And how they want it said. And there is nothing whatever about it that a man worthy to bear important business responsibility cannot learn if he will.” "
This seems to suggest that a patriotic speech he gave was so effective that it even convinced him that he should enlist to go to war.