Next week’s potential relaunch of direct talks between Israeli and Palestinian negotiators represents the culmination of behind-the-scenes diplomacy by Secretary of State John Kerry that began nearly five years ago.

Long before he was sworn in as America’s top diplomat in January, Kerry in 2009 began conducting his own quiet peace process from the Senate through meetings, late-night talks, personal visits, and phone calls with Prime Minister Benjamin Netanyahu, Palestinian Authority President Mahmoud Abbas, and other key leaders in the Middle East. Kerry conducted his shadow diplomacy even as President Obama’s Middle East peace initiative floundered.

To be sure, between 2009 and 2012 Kerry was the chairman of the Senate Foreign Relations Committee, and his contact with these leaders was part of the normal course of his legislative business. But the former Massachusetts senator used his access to Netanyahu and Abbas to test privately what concessions the leaders would be willing to make once he secured his dream job at the State Department, according to U.S. and Israeli diplomats familiar with the meetings and Senate staffers who worked with Kerry at the time.

“He would sit with Abbas and Netanyahu, and he carried messages and received messages and conveyed different points,” said Dan Arbell, who served as Israel’s deputy chief of mission in Washington during that period. “But it seemed more of a sideshow rather than the main event at the time. Now it seems as though he was preparing himself in Obama’s first term for this moment now that he is secretary of State.”

Said Hussein Ibish, a senior fellow at the American Task Force on Palestine: “The secretary himself, during his tenure as chair of the committee, had personal interactions with Abbas and Netanyahu exploring the possibility for other approaches to the peace process, different from what was being done at the time and had been done historically.”

At the center of Kerry’s quiet Middle East diplomacy from the Senate was Frank Lowenstein, the Senate Foreign Relations Committee’s former majority staff director. The staffer and the senator would often travel to the region together, according to Senate aides and State Department officials. While Kerry has strongly formed views of the Middle East himself, his outlook on peace talks was influenced by the low-key Lowenstein.

Known by his colleagues for always trying and failing to quit smoking and being a good listener, Lowenstein has always been one of Kerry’s favorites. The son of Allard Lowenstein, a civil rights and antiwar activist who was murdered in 1980 by a former protégé and was an early inspiration for Kerry’s own career in public service, Frank Lowenstein was a key adviser to Kerry’s 2004 presidential run. That year Kerry compared Lowenstein with his father in a Washington Post profile, saying he had “that same unshakeable faith that he's in this for a reason that's bigger than any of us.”

While Lowenstein is not a foreign-service officer or a Middle East policy expert, some observers say he has the skill set to succeed at Middle East peace where so many before him have failed. While working for the Senate Foreign Relations Committee, he helped negotiate and pass a new Pakistan aid law and also helped manage the process that led to the ratification of the New Strategic Arms Reduction Treaty at the end of 2010. “Frank knows the issues well, and he knows the Washington shoals even better,” said Heather Hurlburt, the executive director of the National Security Network.

Lowenstein took his approach to negotiating legislation to the Middle East and analyzed the impasse in the peace process the way he would count votes, according to one Senate staff member who worked with him. The staffer said Lowenstein “was instrumental in deepening Kerry’s engagement on Israeli and Palestinian issues when he was chairman of the committee. He helped the senator appreciate that the Obama administration had not fully tested the waters on what might be possible in terms of restarting these talks. He got Kerry to travel out to the region several times as chairman to lay the groundwork for later engagement.”

Even after Lowenstein left his Senate post to take a job at the Podesta Group, a major Washington lobbying firm, he was preparing to return to government service with Kerry. He kept in close touch with the senator and continued to advise him on an informal basis. “It was our understanding that the entire time he was at the Podesta Group he was still working with Senator Kerry on a variety of issues, including the Middle East,” said one Podesta employee. While working at the lobbying firm, Lowenstein never registered as a lobbyist, which would have complicated his return to government service due to revolving-door laws.

While Kerry was chairman of the Senate Foreign Relations Committee, his own approach to Middle East diplomacy evolved. In February 2009, when he first took on the role, Kerry led a congressional delegation to Gaza following Israel’s Operation Cast Lead. While he was there, the senator made news by agreeing to deliver a message from Hamas leaders to the White House, a move that rankled Israeli leaders at the time and complicated the new administration’s efforts to start its own peace talks.

A year later, Kerry began to express private doubts about the president’s peace initiative. According to a February 24, 2010, U.S. diplomatic cable made public by WikiLeaks, Kerry raised concerns about the peace process during a February 13 meeting with Lowenstein and Qatari Prime Minister Hamad bin Jassim al-Thani. After Thani said the idea of proximity talks would waste between four and six months, Kerry responded flatly, “We are where we are.” He added that dissent within the ranks of Abbas’s Fatah Party and demands for Israel to freeze all settlement construction meant “the ingredients for the Palestinian people to accept direct talks simply are not there.”

Fourteen months later, Kerry began to voice such criticism in public. Speaking at the 2011 U.S.-Islamic World Forum, sponsored by the Brookings Institution, Kerry said, “I was opposed to the prolonged effort on the settlements in a public way because I never thought it would work, and, in fact, we have wasted a year and a half on something that for a number of reasons was not achievable.”

Eventually, Obama came around to Kerry’s view. By the end of 2010, the Obama administration had largely stopped pressuring Israel to extend the settlement freeze, and the Palestinians refused to participate in any talks with Israel in the absence of such a freeze. In a visit to Israel in March 2013, the president said he would not place any preconditions on Israel or the Palestinians to prepare the ground for new negotiations, a departure from his public pressure on Israel to freeze settlement activity as a condition for talks in his first term.

After Obama departed Israel for Amman in March, Kerry inherited the new peace process the president hoped to restart, State Department officials say. While the secretary at times has seemed to be the odd man out in other important areas, such as Syria and China, on Israel the White House has given him a wide berth.

Kerry has made his own personal diplomacy a high priority in the region. He has already traveled to Israel and the Palestinian territories six times in his first six months on the job. Hillary Clinton, his predecessor, made the trip only five times in her four years as secretary of State.

The White House also has left it to Kerry to choose the U.S. special envoy for Middle East peace. State Department officials say former U.S. ambassador to Israel Martin Indyk is being considered for the job, but no final decision has been made. “You can pick someone who has tried and failed or you can pick someone who has less experience,” one State Department official told The Daily Beast. “That’s the tension right now.”

The White House also has not engaged in any preliminary peace talks with the Palestinians or the Israelis, another key difference from the first term.

Instead, those negotiations have been left to Kerry and Lowenstein, who now serves as the deputy special envoy for Middle East peace and has remained in the region. State Department officials say Lowenstein has been instrumental in the back-and-forth diplomacy that has led Palestinian and Israeli negotiators to agree in principle to come to Washington next week to begin talks about restarting the peace process. If those talks succeed, the staffer and the senator will deserve much of the credit.