Early this summer, Rep. Paul Ryan faced his biggest test yet as a leader who could successfully shepherd major legislation through Congress.

Even House GOP leaders were unsure they could get enough Republican votes to secure passage of trade promotion authority. If the bill failed, it would effectively jettison negotiations on the Trans-Pacific Partnership, the largest trade bill in history.

So Ryan set up his own whip operation to ensure passage of the legislation, which allows the White House to submit trade deals to Congress for straight up-or-down votes without any amendments. Ryan held a number of “education sessions” with Republicans, explaining the intricacies of the trade bill and urging them to overcome their reluctance to give the White House a major win. He argued the bill would hold President Barack Obama “accountable” by laying out detailed negotiating objectives for the White House to meet in any trade deal. Ryan managed to corral 190 GOP votes.

If the past is any guide, the Ways and Means chairman would be an uncommonly detail-oriented House Speaker, more willing to push through obstacles but less resigned to snafus than current Speaker John Boehner.

The education session is a signature Ryan move: A major reason for his credibility with the rank-and-file is the many hours he put in, year after year, going over the fine points of his budget proposals with members of the Class of 2010, sometimes in one-on-one meetings, to make sure everyone understood the numbers. That dogged approach surprised longtime policy watchers and won Ryan plenty of fans in establishment Washington.

Surprisingly, given his reputation as a conservative crusader, Ryan would also be able to work with Democrats on some issues — assuming the right wing that constantly throws sand in the gears of leadership would let him.

Given Ryan's natural inclination toward policy and his attention to legislative detail — a characteristic congressional aides and lobbyists who have worked with him all emphasized — he'd be the kind of speaker who’d want to pore over things like revenue estimates from the Congressional Budget Office. Some worry his nitty-gritty talents would be wasted in the top leadership post, with its constant demands for tending to members and looking at the big political picture.

“He’d be good [as speaker], but it’s not the highest and best use of his skill set,” a former Ways and Means aide said, echoing Ryan’s own statements about the job Republican heavyweights are urging him to seek. (Like most people POLITICO interviewed, the aide wished to remain anonymous given the unsettled nature of the scramble to replace Boehner.)

Giving up his policy role is said to be one reason Ryan is reluctant to go for speaker. After his eponymous budget deal with Democratic Sen. Patty Murray in 2013, Ryan has played a key role in two significant pieces of legislation in his 10 months at the helm of Ways and Means — winning passage of TPA and assisting leadership in overhauling the way Medicare pays doctors.

On other goals, including overhauling international taxes and Temporary Assistance for Needy Families, he’s come up empty-handed. And critics note that Ryan hasn't actually moved piecemeal tax reforms through the panel, beyond one-off extender bills the Senate won't take up.

The legislative maneuvering over fast-track trade authority provides a glimpse at how he might deal with difficult legislation as speaker. At one point, he was nearly outwitted by Minority Leader Nancy Pelosi, who encouraged her caucus to vote down Trade Adjustment Assistance, a Democratic priority packaged with TPA, in order to kill the whole bill. Ryan said he and House Majority Leader Kevin McCarthy quickly decided on the House floor to hold a separate vote on TPA to prove they had a majority even though the legislation couldn’t be passed because the TAA portion of the bill had failed. A week later, they passed TPA.

But the victory also exposed the kind of difficulty Ryan would face as speaker. While his education sessions on TPA worked with most Republicans some conservatives could not stomach giving Obama more authority for anything, despite their past support for trade deals. About two dozen members of the Freedom Caucus voted against the trade bill, including Chairman Jim Jordan, while 13 voted "yes."

Ryan worked with Obama to narrowly win passage despite the overwhelming opposition of Democrats. He has reached out to another Democrat, New York Sen. Chuck Schumer, in an effort to pull off another bipartisan coup on a deal pairing highway funding with international tax reforms. Though the effort stalled earlier this month, the basic outlines of an agreement on the international tax system are there, aides say.

But the two sides started out with fundamentally different goals when Ryan initiated talks. Schumer needs a significant boost in highway funding to get support from Democrats leery of giving multinational corporations a tax break. Also complicating the effort was that many Republicans see mandatory repatriation of funds corporations keep abroad as akin to a tax increase since it ends deferral of U.S. taxation, and using a tax increase to fund new spending won’t fly.

For all Ryan is doing to get bipartisan buy-in from Schumer, he has been unable to secure support from members of his own party in the Senate, where both Majority Leader Mitch McConnell and Finance Chairman Orrin Hatch (R-Utah) are leery of pairing highway funding with repatriation. Hatch also has eschewed Ryan's approach to tax extenders. Ryan moved legislation, on a party-line vote, making 13 of the 50-odd expired tax breaks permanent — a tactic that would lower the long-term revenue baseline and make a future tax reform more GOP-friendly. Hatch, meanwhile, got a package extending all of the breaks for two years through Finance with bipartisan support.

While Ryan's willingness to work with Democrats on at least a few major issues may surprise some given his reputation as a firebrand conservative, congressional Democrats and their aides say they like working with him. Democratic staffers at both the Budget Committee, which Ryan led for four years, and Ways and Means said that while they disagree on policy, they’ve found Ryan accessible, knowledgeable and earnest in his pursuit of policy goals and the occasional common ground.

Part of Ryan’s strategy, a Republican aide said, was to be conciliatory and give Democrats “little things” so that when bigger policy priorities come up they can’t say they’re always left out.

But Democrats who have worked with him believe he’s committed to finding areas of agreement where he can.

“Paul Ryan’s always been open and forthcoming. He seems to genuinely want to get things done, but has been repeatedly inhibited by the far right in his party,” a Democratic aide said.

Many see a shift in Ryan’s approach in recent years: He’s gone from drafting ideologically pure — if largely symbolic — broad-strokes budget manifestos to concentrating on doable, discrete policy tweaks.

“He hasn’t abandoned the view that you should put out what you believe in and go big, and show what you’re for. But I would definitely concede that he is looking more at what you can do and seeking compromise,” a Republican aide said.

Some speculate the change is a result of Ryan’s vaulting to the national spotlight in 2012 as the GOP candidate for vice president — that his new role as a party leader made him feel the weight of actually governing more acutely, shaking loose a tendency to drift into academic debate.