There may not have been a Sen. Elizabeth Warren if it were not for John Walsh.

He helped Warren rise from relative political obscurity to a seat in the U.S. Senate.

Walsh is the respected, admired, and imitated Democrat political operative who died last week at age 65.

At the time of his death, Walsh was U.S. Sen. Eddie Markey’s chief of staff, a position he took after he ran Markey’s successful 2020 re-election campaign, beating off a primary challenge by then-U.S. Rep. Joe Kennedy III.

Markey called Walsh, a one-time Abington selectman and insurance agent, “a political genius” which in many ways he was. Walsh valued grassroots politics and attracting young people to the polls.

Before hooking up with Markey, Walsh played a pivotal role in getting the then relatively unknown Democrat Deval Patrick elected as the state’s first black governor in 2006, and then re-elected four years later.

In 2006 Walsh guided Patrick to a Democrat primary victory over Attorney General Tom Riley and Chris Gabrieli, and then in his November win over Republic Lt. Gov. Kerry Healey.

Four years later Walsh helped Patrick win re-election by defeating Republican Charlie Baker who later was elected governor in 2014 after Patrick declined to run for a third term.

In the interim Walsh served as chairman of the Democrat State Committee from 2007 to 2013, and it was in that capacity that he helped Warren get to the U.S. Senate in 2012.

Back then Democrats were scurrying around to find a candidate to run against Republican U.S. Sen. Scott Brown.

Brown, a state senator, had come out of nowhere to upset Democrat Attorney General Martha Coakley in the 2010 special election to fill the term of longtime Democrat Sen. Ted Kennedy who died in 2009.  Brown was running for re-election to a full six-year term.

Democrats, from President Barack Obama down to Gov. Patrick, had targeted Brown for defeat, but they needed a viable candidate who could win.

While six Democrats had announced their candidacies none were well known or considered strong enough to rally the party and defeat Brown, even though one of them, Marisa DeFranco, a progressive immigration lawyer from Middleton, seemed capable and feisty enough to take Brown on.

Nevertheless, Patrick, who had promised to stay neutral in the fight, along with Walsh and Patrick advisor Doug Rubin, convinced Warren, a Harvard professor with ties to Obama, to make the run.

But they first had to clear the field. Warren needed help. She was a relative newcomer to Massachusetts, was a former Republican from Texas, had no political base, had never held office, and probably could not have won a convention endorsement or a Democrat primary if challenged. She had no convention delegates and voters did not know who she was.

It was Walsh’s job as chairman of the party to get the convention to endorse Warren and nobody else.

Patrick, who had promised to stay neutral, along with Walsh and Rubin cleared the field by persuading everybody to drop out, except for DeFranco.

Smart, articulate, and attractive — and to the left of Warren on many issues — DeFranco believed she would demolish Warren in a television debate. Warren at the time was under fire over her largely imagined status as a “minority” descendant of Cherokee Indians.

DeFranco, and her committed band of followers, gathered the required 10,000 signatures to run at the convention and she was not about to quit.

But it was not to be. Under the convention rules, DeFranco needed to get 15 percent of the delegate vote at the June convention to get on the September primary ballot, a task previously considered routine for candidates.

However, under guidance and pressure from Patrick and Walsh, the party of fairness, diversity and inclusion buried her, and Warren was freed from a primary challenge that could have ended her short political career. Unopposed in the Democrat primary, she went on to beat Brown in the November election.

Some may not have liked it, but it was a political masterstroke.

Markey, who is rarely right about anything, was right about Walsh. He was a political genius, who helped elect two U.S. senators, a governor who served for eight years, and a lot of other people along the way. Not a bad record.

Peter Lucas is a veteran Massachusetts political reporter and columnist.

Ed Markey and Liz Warren also have John Walsh to thank for their Senate seats. (Nancy Lane/Boston Herald)