He did it when Mexico balked, so when the administration’s trade talks with Canada over rewriting NAFTA froze, Jared Kushner moved in to save the deal to give his father-in-law, President Trump, a crowning victory.

Normally a quiet Trump diplomat who works behind the scene, U.S. Trade Representative Robert Lighthizer singled Kushner out as his partner in finalizing the historic trade pact aimed at helping U.S. workers.

“First, the president's key advisor and my good friend Jared Kushner was my partner in leading the U.S. negotiating team,” Lighthizer said at a White House press conference Monday. “I've said before and I'll say again, this agreement would not have happened if it wasn't for Jared. So thank you very much,” he added.

Kushner has emerged at Trump’s secret weapon, especially on trade issues like the newly-minted United States-Mexico-Canada Agreement. He played a central, though unusual, role in bringing Mexico along by reaching out to the country’s foreign minister, an official not typically a leader in trade issues.

On Canada, he used his personal relationship with Prime Minister Justin Trudeau’s Chief of Staff Katie Telford to smooth over raw bureaucratic nerves on several issues.

A key source said that when negotiations faltered between USTR and Canada, Kushner reached out to Telford and see if the two sides could find “common ground” and a deal that both could accept.

“He is able to take things out of the bureaucratic path to keep negotiations going,” said a person with knowledge of the talks. “Jared stays above the noise and when it looked like the sides were not going to get along, he soldiered on and now we’re reaping the benefits today,” added the insider.

Kushner’s evolving and close relationship with Lighthizer also played a critical role. Both trust each other and neither seeks to take credit, as Lighthizer’s press conference comments showed. What’s more, Lighthizer has welcomed Kushner’s help.

As a result, said the source, “Jared has grown extraordinarily close to Bob over the last 20 months and he also certainly feels like Bob’s partner. They work hand in hand.”

Kusher, who also played a key role in other major Trump moves, such as moving the Israeli embassy to Jerusalem and bringing the World Cup and Olympics to the United States, is already turning his attention to the Middle East Peace Process and continuing his efforts for prison reform.