Vice President Kamala Harris’ recent warning to Central American migrants – “Do not come” – suggests the current administration endorses the same wrongheaded approach to immigration as previous administrations.

Immigration is not a drain on the resources of the receiving country. Rather, immigration generates economic growth, entrepreneurship, and other benefits. Research has found immigration to have both positive and negative fiscal effects depending on underlying assumptions; plus fears of negative effects can be addressed by requiring legal immigrants to wait significant periods before benefit eligibility. Indeed, many large federal programs, including Medicaid, SSI, and SNAP, already impose waiting periods on immigrants. Beyond this, research shows that immigrants use welfare and entitlement programs at lower rates than citizens.

In an effort to reduce migration at lawful ports of entry, the Biden administration plans to spend $4 billion on aid to Central America to induce would‐​be migrants to stay put. Research suggests, however, that foreign aid has little effect on economic growth in low‐​income countries and may lead to increased emigration from aid‐​receiving countries.

Instead, one way the U.S. can reduce the flow of migrants is by legalizing drugs, a policy change that makes sense independent of immigration. Increases in homicides are linked to increases in apprehensions of unaccompanied children at the border, and legalizing drugs would eliminate violence from the drug trade, thus creating a safer environment in countries that currently send many immigrants to the United States.

Preventing the free movement of people violates the principles upon which United States was founded. It is possible to preserve national security while encouraging immigration that promotes economic growth. But this requires a welcome mat, not a “do not enter” sign.