The first public opinion poll responding to President Donald Trump’s new policy to control “birth tourism” has just been released and it shows that the move is popular among voters. Even though elite media have been tearing it down as a “way to control women,” public support for the policy shouldn’t be surprising.

Ever since an administrative change by State Department bureaucrats in 1967, the U.S. has been operating under a policy of “birthright citizenship” which awards passports to almost any infant born on American soil no matter what their parents’ immigration status.

Under President Trump’s new regulation, however, consular officers will have the ability to deny visas to pregnant women hoping to give birth in U.S. hospitals. The effort will likely stop many of the more than 30,000 (mostly Chinese) birth tourists who come here annually to take advantage of the policy.

U.S. citizens as well as immigrants who got here by complying with our immigration laws have long expressed frustration over what they see as a giant loophole in the system that needs closing. Still, Sen. Bob Menendez (D-N.J.), one of the Democrats’ louder proponents for mass migration, rejected Trump’s move based on the claim that it is “often advanced by nativist, restrictionist groups.” This is the kind of cheap, lazy and divisive -not to mention wrong -rhetoric that dismisses the views of large segments of the American public.

While immigration reform on many fronts has been a foundation of the Trump presidency, the White House likely got its inspiration from a place that implemented the exact same policy a few years back and with which Menendez is supposed to be well acquainted: Hong Kong.

Hong Kong was one of the last developed parts of the world to curb birthright citizenship, and it did so in a way nearly identical to what the White House recently announced. As the ranking member of the Foreign Relations Committee and a lead sponsor of the anti-Beijing “Hong Kong Human Rights and Democracy Act,” Menendez should know the role which birth-tourism abuse -and Chinese immigration in general -has played in the ongoing tensions between the two regions.

Similar to the violent “umbrella protests” in 2014, the local anger being witnessed today is closely tied to the issue, almost as much as the extradition treaty which sparked the current round protests.

Since 1997, when the then-British colony of Hong Kong reverted back to Beijing, close to 1.5 million mandarin-speaking Mainland Chinese have migrated to the small, dense, majority-Cantonese-speaking region. Numbering just a few percent when the handover happened, Mainlanders (who are viewed by Hong Kongers as being rude, noisy and gauche) now represent close to one-fifth of Hong Kong’s 7.5 million population. Adding to the resentment is Beijing’s near total control over the number of immigration permits given out to Mainlanders and Hong Kong’s inability to change the status quo.

For reasons familiar to most Americans, Mainlander migration has actually long been a source of tension in Hong Kong. According to its post-handover constitution, if a Mainland woman happens to give birth in Hong Kong, her child becomes entitled to birthright citizenship and an automatic right to a Hong Kong passport. Hong Kong citizenship is coveted by Mainlanders because of the access it provides to the local welfare, medical care, education system as well as easier international travel.

But after years of stories in the media about local hospitals being overrun by Mainland would-be mothers, tensions finally boiled over in 2010 when local residents took to the streets in protest. As a result, the Hong Kong government created a law, similar to the new Trump policy, denying entry to those pregnant Mainland women failing to show proof of obstetric appointments in the city and jailing those caught making false claims about their intentions at the border.

Local people, however, are still complaining about Mainlanders overcrowding local hospitals as well as the pressure put on Hong Kong’s welfare system from their mass migration. As a result, local lawmakers have proposed that Hong Kong try to assert greater authority over permit approvals, including a cut to overall numbers and a requirement that applicants prove financial independence before being allowed to immigrate.

These same worries, of course, have also played out in the U.S.; hence, the president’s newly Supreme Court-approved five-year moratorium on welfare use for those hoping to permanently immigrate here. Menendez and other Democratic senators predictably say the policy “frightens people away from critical resources” and “compromises families and communities.”

Few in the world today know the sanctity of national sovereignty and self-rule like the people of Hong Kong. Every day, working- and middle-class Hong Kongers feel the effects wrought on their nation’s quality of life by an immigration system almost completely outside their control.

This is what birthright citizenship is doing in the U.S.: It removes from American citizens their sovereign choice over who and how many can enter the country. The president has taken one small but important step in restoring that.

Dale Wilcox is executive director and general counsel at the Immigration Reform Law Institute, a public interest law firm working to defend the rights and interests of the American people from the negative effects of illegal migration.