The Washington Post: Reports " Trump also criticized Mexican authorities as being too lax about border security, saying the U.S.-Mexico border was “getting more dangerous.” He threatened to “stop” the North American Free Trade Agreement if Mexico does not “stop the big drug and people flows.” "
Lets Get Real:
POTUS wants his wall, he is thinking he got the North Korean leader to a Summit by being tough and being seen as a real threat to the North Korean Regime. Thus the Trump Oval thinks that if he is tough with Mexico he can get a good deal with a new NAFTA. Also NAFTA was seen as the main domestic success of the Bill Clinton Administration, either way Trump wins, if he walks away it will be seen by Trump supporters as a win, if there is a new agreement then Trump can say that only he could get a good deal for the US. Thus as stated a win whatever the outcome. Also if Trump does walk away, it will be seen as another hit for HRC not winning in 2016, it might be petty, but it makes politics fun.