We should not forget that NAFTA passed in late 1993 with Slick Willie in the WH, and with support from almost all Republicans in Congress and opposition from almost all Dims.
I’m sure many Dims will support changes in trade agreements. Trump and Republicans who are with him should refrain from allowing Dims to use support for trade deal changes for any backing off from other part of Trump’s agenda.
Also, as I recall, Al Gore cast the tie-breaker for NAFTA in the Senate.
NAFTA was ratified with 132 GOP votes plus 102 dem votes in the House(234-200) and 34 GOP votes plus 27 dem votes in the Senate(61-38).
But, in 1992, after GHW Bush signed, sealed, and delivered the NAFTA agreement, there were not enough votes in Congress for ratification.
Because, most dems and many GOPers thought that the investor protections were overly extensive while the protections for labor and environment were lacking.
Rather than kill NAFTA, congress agreed to let incoming Clinton negotiate the side agreements to NAFTA that would contain the protections for labor and environment. These side agreements were: North American Agreement on Labor and the North American Agreement on Environmental Cooperation.
Congress would ratify all three agreements, and Clinton would sign the legislation.
But, the side agreements turned out to be toothless because the arbitration panel said that they were not part of the NAFTA document.
Ever since, the dems, unions, and enviros have been agitating to renegotiate NAFTA and put the labor and enviro protections into NAFTA.