On Friday's broadcast of CNBC's "Squawk on the Street," acting Labor Secretary Julie Su responded to International Longshoremen's Association President Harold Daggett's threat to "cripple" the economy by stating that "anyone who's been a part of these things knows that when negotiations are going on, they can get heated, people can say a bunch of things." And "longshoremen play a very critical role in our economy, and this negotiation helped to highlight that."