So When Did We Give the President So Much Unilateral Power on Tariffs?

As most libertarians feared, all those Republican concerns about Executive power under President Obama seem to have magically disappeared now that the President has an "R" after his name.  President Trump is set to put on his magic Thanos glove and snap his fingers and impose 5% Tariffs on Mexico.  The ostensible reason is to force Mexico to reduce immigration to the US, though I think it is becomming pretty clear that Trump actually thinks tariffs benefit Americans and he wants any excuse to impose them on our major trading partners (how about a 5% tariff on Canada if the Raptors win the NBA Finals?).  And all those Republicans in Congress who just 2 years ago nominally 1) were pro free trade; 2) were against raising taxes on Americans; and 3) were against expansions of executive power -- they are just going along meekly.

Scott R. Anderson and Kathleen Claussen attempt to explain what possible legal authority he might have to do so, and it turns out the decision rests on Trump's earlier declaration of a national emergency at the border.

By the way, I know a lot of readers really piled on me every time I tried to compare the border wall to the Berlin Wall.  Didn't I understand that it is totally different to keep people out than to keep them in.  I never thought that made much sense -- the wall blocks free movement of people and I am not sure its morality turns 100% on which side of the border built it.  Perhaps my point is now clearer.  What if Trump convinces Mexico to build the border wall, or at least use more aggresive policing to keep people in Mexico.  Isn't THAT now just the same as the Berlin Wall?