Harry Reid almost never says no.

“When he gets a new piece of information or a request or anything, he says — he uses this phrase all the time — he says: I’ll look at it,” says Ross K. Baker, a distinguished congressional scholar at Rutgers University.

It leaves the Senate minority leader wiggle room to make his own decision in private, a style of leadership that is decidedly different from the “master of the Senate” bull-dozing approach that Lyndon Baines Johnson honed as leader in the 1950s.

That’s just one of the countless insights that Baker, 77, has drawn in three different stints as “scholar in residence” on Reid’s staff. Last week, he finished his final tour with the retiring Senate leader as an unpaid adviser and observer, a one-of-a-kind sabbatical for the Rutgers University professor. Over the past 41 years, Baker has done seven stints on Capitol Hill, working in the House and Senate.

Rather than teaching undergraduate students his “American Government” course, the professor embeds himself in real American government at an irregular pace in the past, but over the past 16 years he’s been here every four years. Nothing can compete with the access he has been given inside Reid’s leadership office in the Capitol. He’s watched the early stages of the 2008 presidential primary play out on the Senate floor between then-Sens. Barack Obama and Hillary Clinton. He’s seen Senate battles over treaties, and, without fail, he’s seen countless legislative battles end in gridlock.

It’s provided history the chance to have an academic get an up close view of one of this era’s most influential figures, but also one of the most difficult to understand.

“The panorama is breath-taking,” Baker said. “Here is somebody who has his pulse on all the major policy areas, has to, and has a staff that is equipped to do that. So the feelers are out, the sensors are everywhere, the neurons are firing constantly.”

Reid said that he wanted Baker to “focus on the Senate as an institution,” for history’s sake, and the professor wrote a 2015 book, “Is Bipartisanship Dead?,” based largely on his 2012 experience with Reid.

“We all trust him,” Reid said in a telephone interview this week from Nevada.

He allowed Baker into every senior staff meeting, as well as let him watch his senior aides prep him every Tuesday morning for his weekly press conference. “He doesn’t speak up very often, but when he does, we all listen,” Reid added.

The low-light came when Republicans filibustered the ratification of a treaty to elevate global standards for the disabled, opening Baker’s eyes to the ability of conservative groups to block legislation.

Now, to his own chagrin, Baker believes the calls on both side for “regular order” — legislation beginning in committee, involving junior members, emerging to full and open debates on the House and Senate floor — are hollow.

“There are just too many forces arrayed against it for it to work,” he said. “I think it’s a function of polarization, that leaders have to get control of the process, and have to use exotic procedures that are basically incomprehensible.”

Yet Reid was never the dictator in Johnson’s 1950s style, according to Baker. Those senators who Reid rebuffed, after his initial “I’ll take a look at it,”would soon find him doing a quick favor. “He will double back and do something for that person to make them feel important,” he said.

Baker has long been known as a leading congressional expert, a go-to for media in need of someone to explain what’s happening in Washington. These stints on Capitol Hill, however, have given him a first-hand experience, spanning decades, that few scholars can match.

Baker’s political interests started randomly. Back in the mid-1970s, when he was fashioning himself an Africa expert and writing occasional op-eds in The Washington Post, Baker decided to refocus his career on U.S. politics and, in particular, Congress.

So he convinced Sen. Walter Mondale’s chief of staff, Richard Moe, to give a break to the 36-year-old professor. Baker read the academic version of Washington in academic journals on his bus commute to the Hill, then lived the real-life version by day, spending a full academic year splitting time among the offices of Mondale (D-Minn.) and Sens. Birch Bayh (D-Ind.) and Frank Church (D-Idaho).

Back then Baker was more like a regular staffer, writing speeches for Bayh and helping Church in his late-breaking bid for the 1976 presidential nomination. He almost accepted Church’s offer of a full-time job, but returned to Rutgers for the fall of 1976 and his first stint teaching “American Government”.

“But I got a serious, you know, a chronic case of Potomac Fever,” Baker said.

By 1983, when his next full-year sabbatical came up, he had landed a gig with the House Democratic Caucus, when the massive majority included dozens of “Boll Weevil” Democrats who backed Ronald Reagan’s tax cuts and strong military.

Baker went another 17 years before he got back to the Capitol, returning to the Senate and to his only Republican boss, then-Sen. Chuck Hagel (Neb.).

He bounced from there into the office of Sen. Patrick J. Leahy (Vt.), the top Democrat on the Judiciary Committee, for several months in 2000 and again in 2004. There, he saw up close how senior senators have to focus on one significant policy arena at the expense of others. For Leahy that meant legal issues and judicial confirmation fights.

“There’s this sort of policy triage that senators have to engage in, which is: They can’t possibly devote themselves equally to three major committee assignments,” Baker said.

Several years later, Baker’s Rutgers connection paid off.

Reid’s longtime senior aide, Susan McCue, was a Rutgers alumna, connecting him with Reid and leading to tours with the majority leader in 2008 and 2012, as well as a brief stint during the 2014 lame duck session. These past four months were Baker’s first stint with Reid in the minority.

With his Reid partnership ending, Baker is returning to another semester of “American Government” this fall at Rutgers. He hopes to get another chance with another senator in four years, even if the “panorama” is not quite as sweeping.

“I at least come out of it with fresh anecdotes for my undergraduates,” Baker said. “I mean, I just don’t want to ever be in a position of mentioning a name and they look at me blankly.”