Gov. Peter Shumlin kicks off his reelection campaign in Burlington, Vt., in September. (Glenn Russell/AP)

Independent D.C. Council member David A. Catania picked up a surprise endorsement from a national Democratic leader Wednesday in his quest to become the first non-Democrat to win the city’s mayoralty.

The endorsement came the same day that new poll numbers showed Catania might also be closing the gap with Democratic nominee Muriel E. Bowser.

The poll, commissioned by Economic Growth D.C., a pro-business advocacy group, put Bowser ahead of Catania by 8 percentage points among likely voters. That’s roughly half of the 17-point gap found last month by a NBC4/Washington Post/Marist poll.

But it was Catania’s endorsement by Democratic Gov. Peter Shumlin of Vermont, the chairman of the Democratic Governors Association, that turned heads in both city hall and in national Democratic circles.

The D.C. Democratic Party sought financial assistance from the DGA and the Democratic National Committee this summer to fight off Bowser’s challenge from Catania. Neither has contributed to Bowser’s campaign.

Instead, in a statement in which he said he had worked with Catania for a decade, Shumlin on Wednesday urged Democrats to vote for Catania over their own party’s nominee. Shumlin cited Catania’s record of successfully expanding health-care access and funding for low-income students. Catania, Shumlin said, “is a leader on the issues that we Democrats care most deeply about.”

Together, the endorsement and the poll numbers allowed Catania to claim momentum heading into a critical two-week stretch of the campaign. The three remaining mayoral debates are scheduled to take place in the next 14 days.

“I was thrilled with the endorsement and with the wording of it,” Catania said. “Having the support of one of the most progressive Democratic governors . . . should lay to rest anyone’s concerns about me. I’ve said all along that I have the most progressive record in this race, and this should give people confidence that I will continue in that direction.”

Catania added that the poll demonstrated that the race “could go either way.”

The poll itself was less clear. It showed that weaker support for Bowser, rather than excitement for Catania, may be drawing the contest closer.

The poll found Catania with similar levels of support among likely voters as last month — 27 percent vs. 26 percent in the NBC4/Post poll. But it put Bowser’s support at 35 percent — unlike the 43 percent reported in the previous survey.

The poll also found softer support for independent Carol Schwartz — 11 percent vs. 16 percent last month.

“What this says to me is the race is closer than a lot of people think it is,” said Dave Oberting, Economic Growth D.C.’s executive director. Oberting said his group paid for the poll in its entirety and is not supporting any particular candidate.

In a mayoral forum Wednesday, Catania warned that Washington is on the precipice of a tougher economic period, suggesting that the election would have far-reaching consequences for the city’s prosperity. Catania suggested that the city’s Democratic leaders, including Bowser, have glossed over troubling economic indicators to keep voters from considering options other than the party that has long controlled the mayoralty.

“As we look at the cranes around our city we have, kind of, a false sense of prosperity,” Catania said. “Our city is in the middle of a recession, and that’s not widely known.”

The District’s economy remains relatively solid, but it has stagnated after years of growth and even contracted in two large employment sectors: the federal government and professional jobs such as legal work. Other troubling signs include rising vacancy rates of office space and apartments, softening of home prices and an uptick in unemployment.

“The District economy has been shrinking for two years — it clearly fits the definition of ‘recession,’ ” said Stephen Fuller, an economist who directs the Center for Regional Analysis at George Mason University. “What’s interesting is that nobody is talking about it. It’s either denial, or it’s that we’re fat enough that we’re taking on water and nobody yet cares.”

Oberting said his group had given economic data to both Catania and Bowser that sounded familiar in Catania’s comments Wednesday at the forum.

It was at that forum, sponsored by D.C. Vote, D.C. Appleseed and the League of Women Voters, that Catania announced the endorsement by Shumlin.

In the endorsement, Shumlin said that as a state senator, he had come to know Catania when the candidate chaired the National Legislative Association on Prescription Drug Prices.

“I witnessed David’s courage in standing up to the pharmaceutical industry on behalf of District citizens,” Shumlin said. “I’ve also seen David bring legislators from around the country together toward a common goal.”

Anita Bonds, chairwoman of the D.C. Democratic Party, sought financial assistance from Shumlin and the DGA as well as from leaders of the Democratic National Committee during the summer. She argued that they should reverse long-standing policies of not contributing to D.C. races to support Bowser. Bonds said she argued that the D.C. mayor is akin to a governor and deserving of DGA support.

“To not be successful in the District of Columbia, that would be difficult to explain to Democrats in Nebraska, to Democrats in Montana, even Democrats in Louisiana,” Bonds said in July. She did not return a phone call Wednesday seeking comment.

DGA spokesman Danny Kanner said Shumlin made the endorsement “in his personal capacity as a friend of Mr. Catania’s, not in any connection with the DGA.”

Bowser did not attend the forum. When asked about the Shumlin announcement, Joaquin McPeek, a campaign spokesman, pointed to a release from the day after Bowser won the primary in April.

In it, Rep. Debbie Wasserman Schultz, DNC chair, is quoted as saying “Democrats are committed to uniting behind Muriel and working to ensure her general election victory in November.”

The DNC also has not contributed to Bowser’s campaign.

Mike DeBonis contributed to this report.