It’s not only the season’s most consequential political event, but also a rare local election with a big rooting interest on the Hill. Voters in the nation’s third-biggest city are deciding next week if they still want to be led by a onetime member of congressional leadership.

If Rahm Emanuel wins a second term as mayor of Chicago, he’ll be cheered by fellow Democrats who remember his central role in engineering the party’s last takeover of the House, almost a decade ago. The victory would also be lamented with equal passion by veteran Republicans, who remember Emanuel as one of the most polarizing partisans in a Congress overstuffed with them.

Beyond that, institutionalists on both sides will be watching Tuesday’s runoff to see whether Emanuel keeps defying one of the more surprising truths about modern politics: Very few politicians succeed in moving from the Capitol to a city hall.

Only one other mayor of a major city is a former congressman. And like Emanuel — who resigned after six years in the House to be President Barack Obama’s initial White House chief of staff, and stayed 20 months before launching his first mayoral bid — fellow Democratic Mayor Tom Barrett of Milwaukee left Congress before being chosen to run his hometown. He gave up his House seat after five terms to run unsuccessfully for governor in 2002, then won the mayoralty two years later. In 2012, Barrett won his third term with 70 percent.

Emanuel doesn’t expect that sort of lopsided triumph over Cook County Commissioner Jesús “Chuy” García, who has become something of a liberal star by portraying the mayor as inadequately interested in the poorer wards. (Independent Sen. Bernard Sanders of Vermont is headed to Chicago Thursday to endorse García and raise money for his own possible presidential bid.) But polls show Emanuel maintaining a solid lead; the most recent survey, published Tuesday by the Chicago Tribune, put him at 58 percent and García at 30 percent.

The current knock on Emanuel, that he’s overly interested in the concerns of the big-money establishment, has roots dating to his early days in national politics. Critics in both parties say he’s been unduly interested in courting and rewarding well-heeled donors since the early 1990s, when he was top campaign fundraiser and then a senior White House aide to President Bill Clinton. After spinning through the revolving door for a short, but lucrative stint in investment banking, a field in which he had no training, he won the House seat covering Chicago’s North Side in 2002. His ascent to the chairmanship of the Democratic Caucus in just his third term was plainly fueled with money. Put in charge of the Democratic Congressional Campaign Committee in his second term, Emanuel raised an astonishing 75 percent more for the political organization than in the previous cycle, cash that financed the party’s spectacular takeover of the House in 2006.

The fact that he left after only three terms, and was already so close to the pinnacle of Democratic power at the Capitol, has some speculating Emanuel, now 55, may be recruited to return to Congress after he’s done being mayor, most likely as a senator. (Though he insists, with typical cuss words tossed in, he doesn’t miss Washington a bit.)

That would put him on a more traditional political trajectory. While it’s a rarity for members to become mayors, taking the reverse route is pretty commonplace — seven former mayors are now in the Senate, along with two dozen former mayors currently in the House. Four once presided over one of the nation’s 50 biggest cities: Democratic Sen. Dianne Feinstein of San Francisco (No. 14), Republican Rep. Kay Granger of Fort Worth, Texas (No. 17), Democratic Rep. Emanuel Cleaver II of Kansas City, Mo. (No. 37) and GOP Sen. James M. Inhofe of Tulsa, Okla. (No. 47).

Some of the most famous big-city mayors of the past century have come straight from the halls of Congress: James Michael Curley of Boston in 1914, Thomas D’Alesandro Jr. of Baltimore (Minority Leader Nancy Pelosi’s father) in 1947, John V. Lindsay of New York in 1965 and Edward I. Koch of New York a dozen years later.

But in the past quarter-century, just two people have moved directly from a House seat to a top municipal post. After 20 years in the House, Democrat Bob Filner was elected mayor of San Diego in 2012, but he lasted just nine months before resigning amid a wave of sexual harassment and battery allegations. Republican Steve Bartlett quit the House early in his fifth term in 1991 to become mayor of Dallas, but after a single four-year term he transitioned into a lucrative career as a financial services lobbyist.

In that same period, by contrast, six House members have tried and failed to win mayoral races — all of their campaigns coming in odd-numbered years when many municipal elections are held, meaning none had to give up their congressional seats to try for the alternate job. All are Democrats, and five remain House members today. John Conyers Jr. got crushed in both the 1989 and 1993 primaries in Detroit. Bobby L. Rush finished a distant second in the 1999 primary in Chicago (a defeat that prompted Obama, then a state senator, to mount his challenge to Rush in the 2000 congressional primary). Xavier Becerra came in fifth in the officially nonpartisan 2001 primary in Los Angeles. Robert A. Brady and Chaka Fattah each collected just 15 percent in the 2007 primary in Philadelphia. And Anthony Weiner was runner-up in his first primary campaign in New York, in 2005. (He got crushed on his second try, in 2013, two years after being driven from Congress by his sexting habits.)

That poor track record may help explain the recent boomlet in members ready to move home to fill a different elected office.

County boards of supervisors in California have real powers over local social services, taxation and economic development — and they tend to be functional without much gridlock. The seats are coveted enough that Gloria Negrete McLeod was unable to secure a spot on the San Bernardino Board last year after a term in Congress. Next year another Democrat, Rep. Janice Hahn, will try a similar semi-sideways move — reckoning that, while a few years of work as a Los Angeles County supervisor may be less prestigious, it affords more opportunities to make a difference than indefinite service in the House minority.

It’s the kind of calculation that Emanuel, had he stayed on his House trajectory these past six years, might be making right about now.

Related:

Does Emanuel Miss Congress? Nope.

2013: House Democrats Pull Pages From the Rahm Playbook

Janice Hahn to Run for County Supervisor

Negrete McLeod Loses Bid

The 114th: CQ Roll Call’s Guide to the New Congress

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