In a surprise victory, Tom Butt was elected Richmond Mayor tonight after a multimillion-dollar campaign by the Chevron Corporation failed to defeat Butt or elect a slate of candidates the giant oil company had supported.

According to tallies as of Wednesday morning, Butt received 51.43 percent of votes, beating his nearest opponent Nat Bates, whose campaign was supported by Chevron, by 16 points.

An ecstatic Butt, speaking from his headquarters, praised his campaign workers and marveled at the unexpected margin of victory: “I’ve never had such a bunch of people who are dedicated and worked so hard. It’s far away above anything that I’ve ever experienced.”

Butt’s election also helped bring victory to a slate of progressive candidates including Jovanka Beckles, Gayle McLaughlin and Eduardo Martinez, who each won a seat on the City Council.

The progressives’ sweep of city hall and the city council further means they’ll be able to fill Butt’s vacated council seat.

A number of observers said that Chevron’s aggressive spending may have backfired.

Uche Uwahemu, who ran third in the mayoral race, said, “The election was a referendum on Chevron, and the people obviously made it clear they did not appreciate the unnecessary spending by Chevron, so they took it out on the rest of the candidates.”

A cheer went up at Butt headquarters when his victory was announced, and his supporters hugged and danced to Butt’s rallying song, “The Arkansas Rattlesnake.”

Butt and the other progressive candidates were considered underdogs in an aggressively fought campaign that involved hundred of thousands of dollars spent against them on billboards, flyers and even a mobile screen. Butt’s comparatively shoestring campaign spent about $58,000. Chevron spending, which totaled over $3 million, attracted national attention to Richmond, a city of 107,000 people.

Voter turnout was low, with an estimated 11,000 people casting ballots. Results are unofficial as more votes are being counted.

After the polls closed at 8pm Tuesday evening and results started coming in, Butt opened up a lead over Nat Bates and held that lead throughout the evening.

“It’s a bloodbath, obviously,” said Bates after the fourth round of results were out. “I think citizens will eventually suffer.”

Bates will retain his seat as a City Council member.

Butt’s campaign manager, Alex Knox, said, “I didn’t expect a full slate victory, but it’s a clear statement. I hope it means that this kind of money won’t be spent the same way again, that maybe it will change how corporations buy elections.”

Chevron’s outlay in the campaign amounted to about $281 per voter, based on tonight’s results.

Progressive candidates in Richmond have gained ground in recent years, embarking on a series of progressive initiatives, including banning plastic bags, increasing bicycle lanes and green-lighting marijuana dispensaries.

Asked about his priorities if elected as mayor, Butt said, “My top priority is to continue the trend towards increasing the quality of life for all in Richmond, making it safer, cleaner, greener, healthier and more prosperous equitably.”

In a statement released today a Chevron spokesman said; “The voters have spoken, and Chevron will work hard to find common ground with this city council to push for sound policies that allow Richmond to grow and thrive. This city, which we have proudly called home for more than a century, has far more opportunities than challenges. The council should remain focused on all those opportunities, and Chevron will continue to work to create economic opportunities for all residents.”

David Thigpen contributed to this article.