If Trump fulfills his campaign promises on immigration, he could disrupt a fragile equilibrium at the southern border and hurt the economy.

Immigration and Customs Enforcement is expected to carry out operations in the coming days to deport undocumented immigrants deemed to be public safety or national security threats. Immigration was a key campaign issue for President-elect Donald Trump and he's expected to use executive powers to restore the "Remain-in-Mexico" policy.

Immigration and Customs Enforcement officials are planning a major enforcement operation that will target immigrants for several days following the inauguration of Donald Trump as president, according to a document reviewed by NBC News and a person familiar with the planning.