At least, you can cherry-pick two who think so (that is how many economists are quoted in the article). On the other hand, you can probably find two economists who will say almost anything. I'm more interested in surveys like the ones the IGM Forum conducts. Here is what they think about the aluminum and steel tariffs:
http://www.igmchicago.org/surveys/steel-and-aluminum-tariffs
I don't really expect the China tariffs to get much better results, but I guess we will see!