US President Donald Trump’s latest attempt to restrict birthright citizenship is expected to face a tough legal battle after the Supreme Court recently upheld broad citizenship rights for babies born in the United States.

Trump signed two executive orders on Thursday targeting what his administration describes as “birth tourism”—when foreign nationals travel to the US to give birth so their children can obtain American citizenship. The move comes just weeks after the Supreme Court rejected Trump’s earlier effort to limit birthright citizenship.

One of the new orders directs federal agencies not to recognise children’s citizenship if either parent is allegedly involved in fraudulent activity to obtain it. Another seeks to restrict visas for foreigners suspected of travelling to the US for birth tourism.

Legal experts, however, questioned whether the measures can survive constitutional challenges. The Supreme Court’s June 30 ruling relied on the 14th Amendment, which provides citizenship to people born in the US who are “subject to the jurisdiction thereof.”

University of Virginia law professor Amanda Frost said that children born on US soil remain citizens regardless of their parents’ illegal conduct. Other legal scholars said some provisions concerning diplomats and foreign government employees could receive different treatment, depending on how they are implemented.

Trump has defended the new measures, arguing that birth tourism is being used to obtain citizenship improperly. His administration is expected to face fresh lawsuits over the orders.