The biggest loser in New Hampshire was NAFTA

And the loser is ....NAFTA. Rather than rehash the political misfortunes left in the wake of the New Hampshire primary vote let us look at long range economic consequences. The two winners, Donald Trump and Bernie Sanders agree on one key principle, NAFTA has to go. Many who should know the answer ask mockingly how Trump could bring the jobs back from Mexico and China. The answer is very simple. He would scrap the trade treaties with both countries. Yes, politics does make strange bedfellows and the thought of Bernie Sanders and Donald Trump standing shoulder to shoulder against Hillary Clinton and what remains of the Republican candidate field only adds credence to the widespread belief of both Sanders and Trump supporters that the system has been deliberately rigged to advantage of the rich and powerful.
Could a President Sanders or Trump simply break a trade treaty? Yes, there is precedence for it. The ultra timid Jimmy Carter unilaterally cancelled a defense treaty. The action was challenged in Goldwater v Carter and the Supreme Court dismissed the challenge without even hearing the legal argument. Similarly George Bush cancelled the ABM Treaty in 2002. But being able to cancel a treaty would not get a President Trump where he would want to be. The absence of NAFTA does not automatically impose tariffs.That would require congressional action and possible compromise with Nancy Pelosi and Chuck Schumer who will be the Senate majority leader in 2017.
My thinking is support for tariffs maybe more popular among the congressional Democratic than the GOP. Only 28 congressional Democrats voted to give Obama fast track authority on the TPP so its reasonable to expect Trump would get little help from his own party. In 2010 Democrat Gene Taylor introduced legislation that would end US participation in NAFTA. It attracted 27 co sponsors;
Rep. Michael Arcuri, D-N.Y.; Rep. Joe Baca, D-Calif.; Rep. Roscoe Bartlett, R-Md.; Rep. Bruce Braley, D-Iowa; Rep. Michael Capuano, D-Mass.; Rep. Jerry Costello, D-Ill.; Rep. Peter DeFazio, D-Ore.; Rep. Bob Filner, D-Calif.; Rep. Raul Grijalva, D-Ariz.; Rep. Phil Hare, D-Ill.; Rep. Maurice Hinchey, D-N.Y.; Rep. Walter Jones, R-N.C.; Rep. Steve Kagen, D-Wis.; Rep. Marcy Kaptur, D-Ohio; Rep. Mike McIntyre, D-N.C.; Rep. Michael Michaud, D-Maine; Rep. Ron Paul, R-Texas; Rep. Mark Schauer, D-Mich.; Rep. Fortney Stark, D-Calif.; Rep. Bart Stupak, D-Mich.; Rep. Peter Viclosky, D-Ind.; Rep. Charles Wilson, D-Ohio; and Rep. Lynn Woolsey, D-Calif.
Note that Taylor and several of the Democratic co sponsors are no longer in the House but there is probably more anti NAFTA sentiment in Congress than there was 6 years ago. Like it or not the prime defenders of NAFTA are "conservative" Republicans. For that reason I turn a deaf ear toward the criticism that Trump is not a conservative. The American worker who has lost his job at Whirlpool or Ford or Nabisco cannot eat the lofty conservative principles articulated by Paul Ryan and the National Review. They seem more intent on preserving Bill Clinton's legacy than restoring the nation.