I seriously doubt that he will deport many millions of undocumented aliens. POTUS Trump is now stating that people who have committed crimes will be deported. He does not want criminals in our country who are not citizens. I think we all support him in this.
It is when we encounter people who are born in the USA and whose parents are not documented - that some common sense agreement will need to be made. Also those who grew to adulthood and have lived quiet lives, working and paying taxes - if they are not criminals, find a solution and a path to citizenship.
Still the number one problem is our unprotected border. It needs to be one of our first priorities - to enforce the border before any other accommodations are devised.
They aren’t undocumented, they have more documents than you do, all fraudulent.
ALL illegal aliens MUST commit myriad crimes DAILY to continue their illegal presence here.
Simple things like driving without license and insurance to working illegally and some much worse.