Immigrants have never been strangers to the Business Journal’s list of Wealthiest Angelenos. With 15 foreign-born billionaires making the cut, a full 25 percent of the list, this year is no exception. That quarter is well represented: Three of the top four were born abroad.

That says a great deal about the opportunity available here, in particular, and in the United States more broadly.

It also should be a cause for concern that the prospects for immigrants becoming wealthy business owners in the United States are growing dimmer. The Trump administration’s immigration crackdown, from legal interpretations that would make it easier for the government to “strip people of citizenship for lying about minor infractions,” to an executive order aimed at reforming the H-1B visa program with the goal of ensuring more companies “hire American,” are worrisome.

Though Donald Trump has been in office less than four months, the impact of his policies are already taking a toll. The University of California system has seen a systemwide drop in the number of international applications this year, which follows a 7.3 percent increase in 2016. Several state universities also saw a decrease in applications from foreign countries, with one Cal State Long Beach administrator telling KPCC last week that the school received queries about “violence toward foreigners and about White House policies that could make it harder for them to get a job in the U.S. after graduation.”

Immigration is, as one person told us, an entrepreneurial act. If there is anyone we want to join us, it should be those people willing to uproot themselves, learn a new language, and immerse themselves in the struggle to succeed in a new land.

It works. Foreign born residents of Los Angeles County account for 51.5 percent of all self-employed workers in the region, according to a study released in February by the Los Angeles Area Chamber of Commerce.

The bar for citizenship should be high. But turning the highly skilled, those pining to study in our universities, and those who would pick our fruit is not only antithetical to the very concept of America, but a bad way to grow the economy and create new generations of wealth.