The administration will need Democratic support too, as the party takes control of the House next year.
Some in the Canadian news media presented the deal as a sign that, at least for now, a full-on trade skirmish had ended. The deal is also subject to a review every six years, at which point the three countries can decide to extend it.
"While there's a lot to like in this new agreement, I'm disappointed that the Section 232 tariffs on Canada and Mexico still remain in place", Republican Senator Rob Portman said in a statement on Friday.
The signing of the new trade deal is a "positive step" toward a trilateral agreement that encourages free trade and the importing of essential products sold in independent supermarkets, such as produce, noted Molly Pfaffenroth, director of government relations at the Arlington-based National Grocers Association, which advocates for the independent grocery sector. A senior White House official said Trump and bin Salman exchanged pleasantries during a subsequent leaders' session.
Trudeau also brought up the recent announcement by General Motors that the company will be closing several factories in both the USA and Canada, calling it a "heavy blow".
Both changes are created to encourage more auto production in the United States in a reflection of U.S. President Donald Trump's "America First" mantra.
"Make no mistake, we will stand up for our workers and fight for their families and their communities", he said, before addressing Trump directly.
Democratic Rep. Jan Schakowsky of IL, for one, said ahead of the signing that it does "not do almost enough to raise wages for workers, lower costs for healthcare consumers, or protect the environment", and that barring major changes, the deal "will result in more broken promises by Donald Trump to American workers".
The signing was done on Pena Nieto's last day in office, a target the countries had pushed for in a bid to have it sealed before his successor, Andres Manuel Lopez Obrador, takes power Saturday.
"Trump made it seem like this was a done deal, but there is a long, long way to go", he said.
The deal comes after more than a year of negotiations between the parties, with agreement on new vehicle and dairy industry regulations proving particularly challenging.
There was a question as to if Trudeau would show up to the signing ceremony. He pinned a medal to Kushner's jacket as Trump and top administration officials looked on.
With his "America First" approach, general distaste for multinational deals and habit of insulting allies, Trump typically gets a mixed reception at global gatherings. The side letters also include deals between the US and Mexico on biologic drugs, cheese names and auto safety standards; and deals between the USA and Canada on wine, water and energy. Yet Trump began the day by illustrating that what was on his mind was the controversy he left behind: the special counsel's investigation of him, his campaign and possible collusion with Russia's interference in the 2016 election.
"I believe that if we don't see more progress at these talks I think Trump will move forward with even higher tariffs on China", Moore warned. Before Trump arrived in Argentina he injected additional drama into the proceedings by canceling another high-stakes meeting, with Russian President Vladimir Putin.