Georges Clemenceau: Doing

“My son is 22 years old. If he had not become a Communist at 22, I would have disowned him. If he is still a Communist at 30, I will do it then.”

Georges Clemenceau

On being told his son had joined the Communist Party, as quoted in Try and Stop Me (1944) by Bennet Cerf
A statement similar in theme has also been attributed to Clemenceau:
A young man who isn't a socialist hasn't got a heart; an old man who is a socialist hasn't got a head.
As quoted in "Nice Guys Finish Seventh" : False Phrases, Spurious Sayings, and Familiar Misquotations (1992) by Ralph Keyes.
W. Gurney Benham in A Book of Quotations (1948) cites a statement by François Guizot as the earliest known expression of this general idea, stating that Clemenceau merely adapted the saying substituting socialiste for republicain:
N'être pas républicain à vingt ans est preuve d'un manque de cœur ; l'être après trente ans est preuve d'un manque de tête.
Not to be a republican at twenty is proof of want of heart; to be one at thirty is proof of want of head.
Variations on this general idea have also been attributed or misattributed to many others, most commonly Winston Churchill, who is not known to have actually made any similar statement.
Post-Prime Ministerial

“The difficulty between us and Germany is this: that Germany believes that the logic of her victory means domination, while we do not believe that the logic of our defeat is serfdom”

Georges Clemenceau

vassalité

Speech to the Senate (10 February 1912), quoted in David Robin Watson, Georges Clemenceau: A Political Biography (London: Eyre Methuen, 1974), p. 220.

Victory

“We need a barrier behind which, in the years to come, our people can work in security to rebuild its ruins. That barrier is the Rhine. I must take national feelings into account. That does not mean that I am afraid of losing office. I am quite indifferent on that point. But I will not, by giving up the occupation, do something which will break the willpower of our people.”

Georges Clemenceau

Speech at the Paris Peace Conference (June 1919), quoted in David Robin Watson, Georges Clemenceau: A Political Biography (London: Eyre Methuen, 1974), p. 352.
Prime Minister

People , Feeling , Indifference

“I think war is inevitable. We must do nothing to provoke it, but we must be ready for it; helped by Russia and England, doubtless by Spain also and perhaps by Italy as well, we may be able to win. In any case it will be a life and death affair: if we are beaten we will be crushed.”

Georges Clemenceau

Letter to Georges Louis (28 July 1908), quoted in David Robin Watson, Georges Clemenceau: A Political Biography (London: Eyre Methuen, 1974), p. 221.

Life , Death , War , Thinking

“In fifteen years I will be dead, but if you do me the honour of visiting my tomb, you will be able to say that the Germans have not fulfilled all the clauses of the treaty, and that we are still on the Rhine.”

Georges Clemenceau

Remarks to Poincaré in Cabinet (25 April 1919), quoted in David Robin Watson, Georges Clemenceau: A Political Biography (London: Eyre Methuen, 1974), p. 352.
Prime Minister

Dead

“I do not know whether war is an interlude in peace, or whether peace is an interlude in war.”

Georges Clemenceau

Speech to the Senate (11 October 1919), quoted in George Bernard Noble, Policies and Opinions at Paris, 1919 (New York: Macmillan, 1935), p. 353
Prime Minister

War , Peace