President Trump announced a trade "understanding" with Mexico Monday that could lead to an overhaul of the North American Free Trade Agreement, saying he wants to get rid of the name "NAFTA." 

"They used to call it NAFTA, we're going to call it the United-States Mexico trade agreement," Mr. Trump said, claiming NAFTA comes with too many negative connotations. 

It's unclear yet if Canada will be a part of any revised agreement — Mr. Trump said "we'll see" if Canada can be a part of the deal with Mexico, or if the U.S. and Canada will need a separate deal. Mr. Trump threatened tariffs on cars if Canada doesn't come to an agreement. 

In the Oval Office Monday, surrounded by reporters, Mr. Trump invited Mexican President Enrique Peña Nieto on the phone for the announcement, although the phone call was plagued with technical difficulties. 

"I thought we would congratulate each other before it got out, and I know we will have a formal news conference in the not-too-distant future," Mr. Trump told Nieto. 

The commander-in-chief according to the White House press pool, ignored reporters' questions about the legacy of Sen. John McCain, who passed away after a battle with brain cancer on Saturday. Mr. Trump reportedly nixed a statement praising McCain, whom he sparred with, and the flags at the White House were at full staff Monday morning when flags at other Washington landmarks were still at half staff. 

"A big deal looking good with Mexico!" Mr. Trump tweeted Monday morning, making no mention of Canada. 

Nieto tweeted just before Mr. Trump's announcement that he spoke to Canadian Prime Minister Justin Trudeau about the status of NAFTA negotiations and progress the U.S. and Mexico have made, and expressed the importance of Canada's involvement in the negotiations. 

Canada points out, however, that its signature is required on any deal.  

"Canada is encouraged by the continued optimism shown by our negotiating partners," said Adam Austen, spokesperson for Chrystia Freeland, Canada's minister of foreign affairs. "Progress between Mexico and the United States is a necessary requirement for any renewed NAFTA agreement. We are in regular contact with our negotiating partners, and we will continue to work toward a modernized NAFTA. We will only sign a new NAFTA that is good for Canada and good for the middle class. Canada's signature is required."

Mr. Trump has derided NAFTA as the worst trade deal ever signed. But it's taken more than 18 months in office to reach any sort of agreement. 

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