Sen. Chuck Grassley Charles (Chuck) Ernest GrassleySenate Republicans face tough decision on replacing Ginsburg What Senate Republicans have said about election-year Supreme Court vacancies Biden says Ginsburg successor should be picked by candidate who wins on Nov. 3 MORE (R-Iowa), the president pro tempore of the Senate, signed the United States-Mexico-Canada Agreement (USMCA) on Wednesday, sending the trade legislation to President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE for his signature.

Grassley, flanked by GOP senators from major agricultural states, praised Trump for his most significant trade achievement, which fulfills his campaign promise of updating the North American Free Trade Agreement (NAFTA).

Democrats came on board after securing stronger labor and environmental enforcement standards, as well as pharmaceutical victories, following months of negotiating with the White House.

USMCA, Grassley noted, was expected to boost GDP growth by .03 percent to .04 percent and add 176,000 jobs.

Grassley and the other GOP senators closed ranks around Trump's trade policies, which have often caused consternation and even pushback among congressional Republicans.

Trump is expected to sign the USMCA as the Senate continues its impeachment trial.

"If you add up the next 27 countries that Iowa does trade with — add them all together, they still don't equal the trade that Iowa does with Mexico and Canada," she said.

“After three years, we’ve seen some success from his trade policies, and USMC is the best example of this right now,” Grassley said.