U.S. President Donald Trump joined leaders from Mexico and Canda in signing the new U.S.-Mexico-Canada Free Trade Agreement. Trump gathered together with Canadian Prime Minister Justin Trudeau and outgoing Mexican President Enrique Pena Nieto on the sidelines of the G20 meeting going on in Buenos Aires. The revised agreement will replace the North American Free Trade Agreement. At the signing, Trump says the new agreement will “change the trade landscape forever.” Now comes the challenging part: lawmakers in each country still need to ratify the agreement. That may prove to be extra difficult in the U.S. because Democrats are taking control of the House of Representatives in January. Several Democrats have already been very vocal in wanting changes to the agreement. The CBC news website says the final vote could even be close in the U.S. Senate. Some Republican Senators have been critical of Trump’s trade policies. However, under the rules of fast-track authority, changes are not supposed to be made after a legal document has been officially signed.