Paul D. Ryan has drifted a long way from the soaring rhetoric he delivered on his first day as House speaker. “Nothing could be more inspiring than a job well done,” he said after claiming the gavel. “Nothing could stir the heart more than real, concrete results.”

Now, the Wisconsin Republican is more likely to sound like a hardened realist, cracking jokes about how little gets done — and even poking fun at himself. As the guest speaker at a black-tie gala Wednesday, Ryan exhorted the media to “keep your heads up” despite poor approval ratings. “It could be a whole lot worse,” he said. “They could be my approval ratings.”

Exactly two years ago Sunday, on Oct. 29, 2015, Ryan, then 45, succeeded Republican John A. Boehner of Ohio, then 65, with an aura of generational change — and a promise of policy-focused leadership.

So far, he hasn’t delivered. Even after Republicans claimed control of both ends of Pennsylvania Avenue in January, Ryan is still searching for a signature achievement. His enemies and allies alike say he needs a big win, soon.

The coming week brings what may shape up as his last, best chance to achieve one — and the most important moment of his 19-year congressional career: the debut of legislation to rewrite the tax code.

House Speaker Paul D. Ryan R-Wis.) and Senate Majority Leader Mitch McConnell R-Ky.) announce plans for tax legislation in September. (Melina Mara/The Washington Post)

Taxes are supposed to be Ryan’s issue, his policy wheelhouse. As the disciple of the 1980s fiscal conservative Jack Kemp, Ryan’s rhetoric is never loftier than when espousing free-market principles and the belief that lower taxes and a streamlined code can help businesses, the economy and even the impoverished.

He has craved this moment. He also has good reason to dread it.

A major question is whether much has changed since an unruly House Republican Conference, as the caucus is known, forced Boehner out and ground governance to a halt. The conference remains deeply turbulent under Ryan — and divided, particularly on the issues of taxes, spending and the national debt.

Failure to advance tax legislation — even if defeat comes in the Senate, as happened in July with legislation to revise the Affordable Care Act — would be crippling. One possibility if Republicans head into 2018 having to explain why they failed on both health care and taxes: a political bloodbath that drops the GOP into the minority and boots Ryan off the dais.

“The 115th Congress, if we go zero for two, gets a failing grade,” said Rep. Mark Walker (R-N.C.), the leader of one of the House’s conservative caucuses. “I think a lot of us may not come back.”

Tax reform, in Ryan’s ideal, was supposed to be bigger than tax cuts. It was supposed to be revenue-neutral — lowering some taxes, raising others, closing loopholes and simplifying the code. It wasn’t supposed to be so easy to criticize for lowering taxes on corporations and higher-income Americans.

President Trump has complicated the challenge by rejecting Ryan’s branding of tax “reform” — instead calling the effort “tax cuts” and sometimes “tax cuts plus.” The president may not be wrong about that distinction, but he has contributed to a mashed-up message on what the bill would actually do, whom it would benefit — and importantly, how much it would cost.

Even modest tax legislation would in some ways fulfill Ryan’s calling — and offer some much needed momentum to Republicans heading into potentially difficult midterm elections next year.

But it requires something that the GOP caucus has long been loath to consider: compromise. In the Boehner days, the “grand bargains” that Republican leaders sought with then-President Barack Obama frequently ended in ignominious defeat. Skeptics remain dubious that this year’s bargain will end any differently.

“I think the broken process has not been fixed, and there are some aspects that have gotten worse over the past few years,” Rep. Justin Amash (R-Mich.), a member of the rebellious Freedom Caucus.

One problem, Amash said, is that Ryan’s promise of a bottom-up approach has not materialized. Ryan has won some credit for earlier engagement with the GOP’s restive wings, including a weekly lunch with representatives of the Freedom Caucus, Walker’s Republican Study Committee and the moderate Tuesday Group. But as Amash noted, “It doesn’t mean they are actually taking our input.”

Unlike past years, the GOP moderate wing is a big part of Ryan’s challenge. Aspirational and even wonky ideas — repealing the ACA, for instance — were easier to vote for with the certainty of an Obama veto across town.

Voting on legislation that could become law is harder — and moderates have put up a bigger fight this year, on both health care and taxes, than in any of the previous six years of the House GOP’s tenure in the majority. These moderates nearly defeated the budget outline that passed Thursday, including enabling language to pass a tax bill, because the emerging tax proposal might eliminate the federal deduction for state and local taxes — a big hit to workers in the blue states where many of these moderate lawmakers live.

“If you have the Freedom Caucus, and you have New York and New Jersey, you’re talking about two opposite ends of the spectrum — and a president who sometimes goes his own way,” said Rep. Peter T. King (R-N.Y.), who voted against the budget outline.

In the Trump era, no one seems particularly happy with Ryan.

Some in the conservative intelligentsia, who spent years promoting him, have turned against him for not denouncing whom they see as an anti-intellectual president who rejects Kemp’s free-market, supply-side philosophy. Staunch Trump supporters don’t trust Ryan because of his wobbly support during the 2016 campaign.

Democrats now suspect that Ryan, historically unpopular in national polling, might be a more effective boogeyman than Trump in TV ads against Republican incumbents.

Liberal satirists have published a 192-page parody magazine devoted to mocking Ryan, poking fun at "the most unpopular politician in America" and his image as thoughtful policy prince who never delivers.

And yet Ryan still has strong support from the people who matter most in keeping his job: House Republicans — even those facing tough campaigns next year. “Speaker Ryan is always welcome in New Jersey. He’s always welcome in New Jersey,” said moderate Rep. Leonard Lance (R-N.J.).

Ryan, married with young children, dreaded that part of the job when he took the post two years ago — the endless fundraising and travel. But he’s blown away the very high cash levels that Boehner hauled in, in part because big donors prefer talking to a high-profile former vice-presidential nominee over the genial but less meaty Boehner.

In a cruel twist, failure to enact policy could be Ryan’s downfall.

For the past 30 years, every speaker, Democrat or Republican, has left the job on bad terms, either losing the majority or being chased out by their own party.

Ryan will find out soon whether he’s about to continue that trend.

“If we’re still batting zero on these large items, when it comes to next year, I don’t think he’ll be by himself,” said Walker. “I think a lot of us will be in trouble.”

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