... If all those pundits [who criticized Trump's demand for extreme vetting of immigrants] had bothered to do just a couple of minutes of googling before reacting, they would have discovered that immigrant vetting, and even extreme immigrant vetting, has a very long tradition in American history. Since before the founding even, U.S. policies about whom the country chooses to welcome and reject have changed in response to changing conditions. As early as 1645, the Massachusetts Bay Colony prohibited the entry of poor or indigent persons. By the early 20th century, the country was filtering out people who had “undesirable” traits, such as epileptics, alcoholics and polygamists. Today, the naturalization oath demands that immigrants renounce allegiance to any foreign state. Even our Favorite Founding Father du jour, Alexander Hamilton (himself an immigrant), thought it was important to scrutinize whoever came to the United States. He wrote:

To admit foreigners indiscriminately to the rights of citizens, the moment they put foot in our country … would be nothing less, than to admit the Grecian Horse into the Citadel of our Liberty and Sovereignty. … The United States have already felt the evils of incorporating a large number of foreigners into their national mass. … In times of great public danger there is always a numerous body of men, of whom there may be just grounds of distrust; the suspicion alone weakens the strength of the nation, but their force may be actually employed in assisting an invader.

In other words, immigration vetting is as American as apple pie.

In the colonial era, governments were particularly concerned with the entry of “public charges” who could impart substantial costs on the indigenous population. In 1691, the Province of New York must have hired a professional economist to design a bonding system that would discourage the entry of people who would be a drag on public resources:

All Persons that shall come to inhabit within this Province ... and hath not a visible Estate, or hath not a manual occupation, shall, before he be admitted an Inhabitant, give sufficient surety, That he shall not be a burden or Charge to the respective places, he shall come to Inhabit. Which Security shall continue for two years.

And in 1740, Delaware enacted legislation to “Prevent Poor and Impotent Persons being Imported." Many of these colonial-era restrictions remained in place until 1875, when the Supreme Court invalidated state-imposed head taxes on immigrants to fund the financial burden of caring for poor entrants, and made immigration the sole purview of the federal government. But that wasn’t the end of immigrant filters. Congress responded by creating the vetting system that—although modified many times—remains in place today. In 1875, Congress prohibited the entry of prostitutes and convicts. In 1882, Congress suspended the immigration of Chinese laborers, and added idiots, lunatics and persons likely to become public charges to the list for good measure. ...