On Thursday I was up at the Hoover Institution to do the interview with Erin Ade of RT's BoomBust and I always use those chances to visit some of my favorite Hoover colleagues. One of them is Alvin Rabushka, who invited me into his office and showed me the flags he has from each country or political entity that has introduced the flat tax rate on income. Alvin, with our fellow Hoover colleague, Bob Hall, wrote the book The Flat Tax, and Alvin has proselytized for a flat tax around the world. The picture below shows the results. Every flag on that desk represents a place that adopted the flat tax.