From time to time our national history has been marred by forgetfulness of the Jeffersonian principle that restraint is at the heart of liberty. In 1789 the Federalists adopted Alien and Sedition Acts in a shabby political effort to isolate the Republic from the world and to punish political criticism as seditious libel. In 1865 the Radical Republicans sought to snare private conscience in a web of oaths and affirmations of loyalty. Spokesmen for the South did service for the Nation in resisting the petty tyranny of distrustful vengeance. In the 1920s the Attorney General of the United States degraded his office by hunting political radicals as if they were Salem witches. The Nation's only gain from his efforts were the classic dissents of Holmes and Brandeis. In our own times, the old blunt instruments have again been put to work. The States have followed in the footsteps of the Federalists and have put Alien and Sedition Acts upon their statute books. An epidemic of loyalty oaths has spread across the Nation until no town or village seems to feel secure until its servants have purged themselves of all suspicion of non-conformity by swearing to their political cleanliness. Those who love the twilight speak as if public education must be training in conformity, and government support of science be public aid of caution. We have also seen a sharpening and refinement of abusive power. The legislative investigation, designed and often exercised for the achievement of high ends, has too frequently been used by the Nation and the States as a means for effecting the disgrace and degradation of private persons. Unscrupulous demagogues have used the power to investigate as tyrants of an earlier day used the bill of attainder. The architects of fear have converted a wholesome law against conspiracy into an instrument for making association a crime. Pretending to fear government they have asked government to outlaw private protest. They glorify "togetherness" when it is theirs, and call it conspiracy when it is that of others. In listing these abuses I do not mean to condemn our central effort to protect the Nation's security. The dangers that surround us have been very great, and many of our measures of vigilance have ample justification. Yet there are few among us who do not share a portion of the blame for not recognizing soon enough the dark tendency towards excess of caution.