Total nonsense that's been repeated so often some people have been brainwashed into accepting it (or they are actually open borders believers). Any president who desired it could begin enforcing immigration at the employer level today.
We see the result in every state that passed their own laws; illegals begin to leave, often just in anticipation that the new laws will be enforced.
That "secure the border first" is the Juan McCain Ruse that he used in 2008 campaign and during his 2010 senate reelection campaign. It's nonsense, and nothing but the latest procrastination technique by politicians who have no intention of enforcing the law, now or later.
That's a good thing. And I don't have a problem with enforcing the laws at the state level. We do it here in Georgia. But we were talking about some people like I know, who have been here for 25 years or more, own a home, have children in school who were born here, and have worked and paid taxes here for 25 years or more. Yes, I do know some too. Should we just deport the parents now, but allow the kids to stay? Or have some kind of a panel look at the facts in such cases, and make some exceptions?