The G stands for Gamaliel, of course.
A pleasant message, but one with overtones that might have disturbed some American Jews (or Jewish Americans) at the time. In describing "the American nation" as among the friends and well-wishers of "the Jewish people," where did that leave the Jews of America? My maternal grandfather, an Ohio Republican like Harding who proudly identified himself in 1922 as Orthodox, anti-Zionist, and American, might have been among those taking exception. On the other hand, his future wife, also American born but a lifelong Mizrachi adherent, might not have been bothered at all.