In his social media post, Trump proposed testing the Alliance's validity by forcing its forces to counter an "invasion" of illegal migrants, APA reports.
According to the president, this would free up American border guards for other tasks.
"Perhaps we should have tested NATO: invoked Article 5 and made NATO come here and protect our southern border from further invasions of illegal immigrants, thereby freeing up a large number of border patrol agents for other tasks," Trump wrote.