Fifty years ago last week, on Feb. 26, 1964, President Lyndon B. Johnson signed into law the sweeping tax cuts that had been championed by his predecessor, John F. Kennedy. The law brought the top marginal income tax rate down to 70 percent from 91 percent and the bottom marginal rate down to 14 percent from 20 percent. The 22 rates in between also were cut.

The tax legislation of 1964 was one of three major across-the-board income tax cuts in the 20th century. The others took place in the 1920s, during the Warren Harding and Calvin Coolidge administrations, and in 1981 and 1986 during the Ronald Reagan administration. After the Tax Reform Act of 1986, the top marginal rate was all of 28 percent. Today, it is 39.6 percent.