This has prompted discussion about what could happen, and Trump revealed on Friday that there is a "good chance" he will declare a national emergency to circumvent Congress and build a wall along the US-Mexico border.
His comments have sent a wave of unease through politicians in the US, both republican and Democrat alike.
Republican Chris Stewart doesn't like the idea of going around congress to push through the Wall - but not for the reason you think.
Talking to reporters, he said:
If we declare a national emergency to build a few hundred miles of fence, my fear is what is the next democrat going to do when he or she thinks that climate change is a national emergency...It opens a pandora's box.
Rep. Chris Stewart: "If we declare a national emergency to build a few hundred miles of fence, my fear is what is t… https://t.co/TCVgcqFJH0