Immigration may be the No. 1 issue on Donald Trump’s priority list. Trump promises to massively deport millions of undocumented migrants if he wins the election.

At a rally in Colorado, Asset said it would target “all illegal migrant criminal networks operating on American soil.” His plan is to use a 1798 law “previously used to detain ‘enemy aliens'” in times of war, said Axios. Critics say the Alien Enemies Act of 1798 could also be used to detain “legal immigrants and their American-born children.” But a Trump spokesperson said Americans “want mass deportations of illegal immigrants and have more confidence in President Trump on this issue.”