The Treaty of Guarantee came out of a proposal by Lloyd George, the British Prime Minister, at the allied conference of Paris as a compromise to Marshal Ferdinand Foch's insistence that the Franco-German border be pushed back to the Rhine. Foch felt that this new border would prevent another German invasion into France. The Germans had invaded France from across the Rhine five times within a century in 1814, 1815, 1870, 1914, and 1918. Its terms called for solemn guarantees by Britain and America of the French frontier against future German aggression.
William L. Shirer