Federal Reserve

Janet Yellen, the most important person in DC in 2015

Congress still has some serious unfinished business for 2014, including passing a funding resolution keeping the government opened past Dec. 11 and extending popular tax provisions and terrorism insurance.

But let's err on the side of hope for a moment and assume the lame duck session manages to stumble to a solution that avoids a shutdown while letting conservative GOP House members vent against the White House over President Barack Obama's unilateral immigration executive order.

That solution could conceivably take the threat of shutdown off the back of the economy until next October while possibly only funding immigration-related agencies until early next year as Republicans ponder options for responding to Obama.

Instead of handicapping odds for a shutdown, let's look forward to 2015 and the biggest storylines that will dominate the intersection of Wall Street and Washington.

They will no doubt involve Congress and the possibility of a showdown over the debt limit in the spring and possibly renewed fights over running the government. But most of this will be familiar territory likely to end in familiar ways, without glory but without catastrophe.

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And there will of course be the running story of the emergence of 2016 candidates in the GOP and the possibility that Hillary Clinton draws a significant liberal challenge in the Democratic presidential nominating contests. She probably won't, but she is far from a lock to win the White House.

The more interesting and nuanced storyline is likely to involve the Federal Reserve and Chair Janet Yellen.

Janet Yellen
Paul J. Richards | AFP | Getty Images

Yellen has a daunting set of tasks before her. She must manage the continued shift away from extraordinary assistance to a more normal policy footing without stomping on the brakes too fast and sending the U.S. economy crashing back into recession.

And she must do it while Europe, Japan and even emerging economies including China suffer and the world grows increasingly dependent on U.S. growth. The big challenge, of course, will be smooth communication to markets on when and how rates will start to rise now that U.S. joblessness is falling back to normal levels and wage growth is likely (but not certain) to follow.

There is no roadmap for communicating the upcoming shift in policy because it's never been done before. And the "Taper Tantrum" of 2013 shows just how sensitive markets are to even hints of the Fed choking off the easy money spigot.

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"It is essentially impossible to know how markets are going to react and how bad things are going to be and how vulnerable the economy is going to be to that reaction," Lewis Alexander, chief U.S. economist at Nomura and a former Fed official, said in an interview. "That is a problem the Fed faces, and there is pretty much no way around it."

There is also no way around the fact that Yellen is going to be attempting to lead the Fed through a complex policy shift just as the GOP takes full control on Capitol Hill and pushes hard for an "Audit the Fed" bill that could subject the decision-making process of the central bank's policy-making committee to unprecedented scrutiny.

The House and Senate could pass audit bills that require the Government Accountability Office to conduct reviews of both the Fed's books as well the Federal Open Market Committee's decision-making process on rates and other monetary matters.

Current and past Fed governors are terrified that this would lead to naked political pressure on the Fed to act in ways that are intended to please politicians rather than assist the economy.

Should the Fed's decision making be subject to real-time public review rather than the current five-year delay, the thinking goes, the central bank will lose its coveted independence from a currently dysfunctional political system.

Republicans say they just want the Fed and its $5 trillion balance sheet to be subject to more accountability and transparency. Central bank officials counter that the books are already subject to extensive audit and the FOMC disclosure regime is already very carefully calibrated to balance transparency with the need for members to feel free to openly discus all possible actions without fear of upsetting markets or political bosses in Congress.

And the pressure on the Yellen Fed won't come just from the right. Populist Democrats led by Sen. Elizabeth Warren, D-Mass., will pressure the central bank to upgrade—or be stripped of—its Wall Street oversight role. Many anti-big bank Republicans are likely to join this effort as well, making for uncomfortable hearings for Fed officials including regulatory chief Daniel Tarullo.

Taken together, all of these pressures suggest the Fed may be the real center of consequential action in D.C. next year even if there is a lot of noise coming from Capitol Hill and the campaign trail.

—Ben White is Politico's chief economic correspondent and a CNBC contributor. He also authors the daily tip sheet Politico Morning Money [politico.com/morningmoney]. Follow him on Twitter @morningmoneyben.