Joshua Roberts / Reuters U.S. President Donald Trump speaks at a campaign rally in Phoenix, Arizona, August 22, 2017. Trump told the audience that the U.S. will

WASHINGTON — He can huff, and he can puff, but can Donald Trump really single-handedly blow NAFTA down? It's more than fairy-tale conjecture now. It's a question of practical importance as the president has now demonstrated he intends to wield it as a threat during negotiations. The Canadian Press has gathered analysis from 10 trade-law experts in an attempt to settle that question, some via interviews and others via research papers that explored the limits of presidential power to end the trade deal. Here's the one thing everyone agrees on: It would get messy. That much is clear. There's widespread consensus that it would trigger a period of uncertainty, marked by court fights between the White House, industry groups, state governments and possibly federal lawmakers. The reason it's such a legal question mark is that it has never happened before. A paper for U.S. lawmakers by the Congressional Research Service last year said the United States has never cancelled a free-trade agreement and has only suspended one, the original deal with Canada which was replaced by NAFTA. The latest on Donald Trump and NAFTA:

A presidential scuttling of NAFTA would create a historic conflict. On one side would be the powers of the presidency, which include foreign affairs, control over tariffs delegated through various laws, and the provision in NAFTA that allows him to cancel the deal on six months' notice. On the other side is Congress, which has constitutional power over international commerce and duties; which passed a law to implement NAFTA; and which could argue that the president's withdrawal violates that 1993 law. Tim Meyer thinks Congress would win. "If the president were to rip up NAFTA and then sort of jack tariffs way up, I think somebody would be able to come in and say ... 'You're actually violating U.S. domestic law'," said Meyer, a Vanderbilt professor, former government lawyer, and one-time clerk for Neil Gorsuch, whom Trump appointed to the Supreme Court. "I think courts are going to be sympathetic to the idea that the president can't ignore the legislation that implements these trade agreements. Congress has not repealed that legislation and they've given no indication they intend to.''

Joshua Roberts / Reuters U.S. President Donald Trump speaks at a campaign rally in Phoenix, Arizona, U.S., August 22, 2017.