The conventional wisdom about South Bend Mayor Pete Buttigieg’s presidential candidacy has seemed incontestable: He may be smart, sensible and appealing, but he hasn’t a prayer of winning the 2020 Democratic presidential nomination. With Buttigieg’s surge in polls of potential caucus-goers in February’s Iowa caucuses, however, that bit of conventional wisdom, like other conventional wisdom that has imploded in recent presidential campaigns, may end up as stale as last month’s bread. The hard fact is that Buttigieg could win the Iowa caucuses, and if he does, his candidacy, fueled by momentum, a potentially endless flow of campaign contributions and the advantage of seeming the fresh face in an old and tired Democratic field, could reshape the Democratic nominating process overnight.

Friday’s New York Times/ Siena poll found Buttigieg in a statistical tie for first place in Iowa, in a dead heat with Elizabeth Warren, Bernie Sanders and Joe Biden. This was no outlier; an Iowa State University poll taken the previous week had him in a strong second place, with 20% of surveyed caucus-goers in his camp. That, in turn, was on the heels of yet another poll showing him essentially tied for first place. Buttigieg’s Iowa surge is real, and it has been boosted by the young mayor’s intrinsic likability, his barnstorming tours across the Hawkeye State and millions of dollars of cash on hand provided by a highly successful fundraising effort.

Nor did Buttigieg hurt himself with a fine performance at Iowa Democrats’ Liberty & Justice Celebration in Des Moines on Friday night. Over 2,000 of his supporters showed up at the arena in which the gathering was held and, not for the first time, their candidate delivered the cleanest, clearest rebuke to Donald Trump. “The purpose of the presidency,” Buttigieg told the audience, “is not the glorification of the president but the unification of the American people.” The clean-cut Afghanistan veteran, who has exuded midwestern decency since launching his candidacy, presents to many Americans as the equivalent of a deep, cleansing bath after the slime shower inflicted on the nation over the past three years. “Pete comes across to people as absolutely authentic,” said former Democratic National Committee chairman Steve Grossman, who has endorsed Buttigieg. “Likability trumps almost everything else in American politics. It is highly possible that Pete can do extraordinarily well in Iowa.”

A Buttigieg victory in Iowa is a distinct possibility, and one that would upend the political card table. His still-strong national poll numbers notwithstanding, Biden is in trouble. His cash on hand available to slug it out in the early primary states and still prevail in the cross-country nomination battle to follow is very low, his fundraising hampered by dependence on maxed-out big donors. His candidacy is startlingly devoid of support from young or even middle-aged voters; the New York Times/ Siena poll found that only 2% of Iowa Democrats under age 45 support the former Vice-President. He appears headed to a fade-out, and a likely fourth place finish in Iowa will hasten his fade.

A Buttigieg win would deal a blow to Warren’s basic strategy: to win Iowa, ride a momentum-driven rocket into New Hampshire, win there and roll over a flattened Biden to win the nomination. Instead, it would be Buttigieg who would be poised to win New Hampshire in a multi-candidate field. Warren would have to duke it out with Buttigieg in primary states across the country that feature Democratic primary voters more hospitable to Buttigieg’s more moderate views than those of Warren, whose hold on progressive Democrats will be challenged by Sanders right through the Democratic convention.

Expecting the unexpected has proven the safest course in recent presidential elections. Buttigieg’s sudden emergence as a serious contender in Iowa is a reminder of how many surprises are out there waiting to surprise us.

Jeff Robbins is a Boston lawyer and a former U.S. delegate to the United Nations Human Rights Commission.