United States Politics: ∆τ_i*ε*φ*m_i<0 where ε=4 and φ=0.25

[Potato]

They really don't know. Watch the markets. If they had confidence then it wouldn't be like this. Consumers don't know either. 

Tariffs are like a horseless carriage to people.

Oh, so when you say "they" you mean the gormless masses without even a basic understanding of economics...people like Trump. 

Economists do know and the US government knows as evidenced by the first link. Historians know too because they understand that the world has always suffered when protectionism has been popular and has advanced when free trade is encouraged.