"Show me a young Conservative and I'll show you someone with no heart. Show me an old Liberal and I'll show you someone with no brains."

(). The phrase originated with François Guizot (1787-1874): "Not to be a republican at twenty is proof of want of heart; to be one at thirty is proof of want of head." It was revived by French Premier Georges Clemenceau (1841-1929): "Not to be a socialist at twenty is proof of want of heart; to be one at thirty is proof of want of head."

Referenced in Swimming with Sharks (1994) as "if you're not a rebel by the age of 20, you've got no heart, but if you haven't turned establishment by 30, you've got no brains."