I won't rehash my opinions, they already been better said here, but I want to add I hate the phrase "close the border". What the fuck does that mean, was it open, did the last one in forget to close the door?
From the article, he is considering taking action "to restrict migrants’ ability to seek asylum at the US-Mexico border if they crossed illegally" which has a lot more nuance and is important to the discussion. So this will specifically affect people who have a legitimate claim to asylum, the border was never "open" to any migrants without it (or a visa).
I think that's why framing the debate is so important.
And so on. This isn't about stopping immigration, it's about punishing those who do. [Too] Many will still support that, but it's a harder stance to take.