Chris Christie is positioned for a bounce in popularity in Iowa as signs grow that Republicans here are giving him a fresh look.

Crowds at the Republican presidential hopeful’s Iowa events have grown by hundreds in the past month, and the number of Iowans willing to commit to join his campaign has jumped, aides say.

“His momentum is really just starting, and he’s got perfect timing with the caucuses less than a month away,” said Adrianne Branstad, a 35-year-old Des Moines Republican who has endorsed the New Jersey governor.

Christie still has poor poll numbers: He was tied for sixth place with just 3% support in the early December Des Moines Register/Bloomberg Politics Iowa Poll. But even as he catches flak for not spending enough time governing New Jersey and his approval rating sinks there, some GOP caucusgoers in Iowa are warming to him.

His image rating improved by 18 percentage points, from 28% who viewed him favorably in May to 46% in December, Iowa Polls show.

Earlier in the 2016 race, Christie was focusing almost exclusively on New Hampshire, whose more-centrist Republicans cast ballots a week after the Feb. 1 Iowa caucuses. But the top two mainstream Republican contenders — Sen. Marco Rubio of Florida and former Florida Gov. Jeb Bush — haven’t closed the deal in Iowa yet, leaving the door open to Christie, his strategists say.

The aim isn’t to win Iowa, just to beat Bush here and slow Rubio’s momentum.

“I think we’ll do well in Iowa, and I think we’ll do very well in New Hampshire,” Christie said on Fox News in mid-December.

Meanwhile, Rubio is making huge late-in-the-game investments in Iowa, signaling he’s trying to come out in second place — Sen. Ted Cruz of Texas and New York businessman Donald Trump hold the top two spots now — or win Iowa outright.

Rubio now has the most Iowa offices of any GOP candidate, four; he’s running the most Iowa TV ads; and he has one of the largest Iowa teams with 16 paid staffers. Only Bush has more with 20 staff working from two offices.

Christie, who has lacked the money to spend much in Iowa, has five paid staff and a single office in Johnston, Iowa.

One indication Christie’s rivals are getting nervous that his support is growing: Super PACs for Rubio and Bush have targeted him in negative ads, but so far only in New Hampshire, not in Iowa.

If Christie rises in Iowa, his rivals likely will begin to go after the relatively moderate or liberal positions he’s taken to get elected in a blue state like New Jersey, strategists said. And critics question whether he could he attack Democratic front-runner Hillary Clinton in the general election as being “scandal prone” when he has faced questions about his own administration.

In response, Jeff Boeyink, Christie’s chief Iowa adviser, said Christie at the end of the day is the only one in the race who has been able to get anything positive done while Democrats held majorities, including public pension reform.

“It’s remarkable what Chris Christie accomplished with super-majorities in both chambers working against him,” Boeyink said.

Here are seven reasons Christie is poised for a possible rise in the polls in Iowa:

1. Sparks on the campaign trail

Christie attracted about 250 to his event in Cedar Rapids last week and about 400 in Waukee. Those aren’t Trump-sized crowds, but they’re records for Christie, whose previous high was about 200 in Scott County.

Sharon and Mike Fontanini, both Waukee residents who work in sales and describe themselves as moderate Republicans, were “very impressed” with Christie’s event at an Irish pub in Waukee last week.

“We were for Rubio, but now we’ve changed to Chris Christie, and I would say we’re pretty firm,” said Mike Fontanini, 65, who has gone to Iowa rallies for Christie, Rubio and Mike Huckabee. “Christie seems to be a little more experienced.”

2. Approach tailor made for Iowa

There’s a reason Christie was the top surrogate for 2012 Republican presidential hopeful Mitt Romney in Iowa. Iowa is a place that embraces “retail” campaigning, and Christie has a special talent for it, Iowans in his audiences have said.

“He’s very good at face-to-face politics and has vast knowledge on almost any topic people bring up,” said presidential paparazzi Monte Goodyk, an Iowa Republican who has attended a plethora of campaign events in Iowa as he films footage for a documentary called The Nominee.

“Chris Christie is like Donald Trump in a tell-it-like-it-is sort of way, but unlike Trump, actually takes time to talk to individual Iowans instead of just waving from a stage and signing hats,” Goodyk said.

3. A focus on centrist voters

To target center-right Republicans, he has focused on more blue-collar industrial towns in central and eastern Iowa — Cedar Rapids, Fort Dodge, Jefferson, Newton,Marshalltown, Muscatine, the Quad Cities — than rural areas.

But he has ventured twice into deeply conservative northwest Iowa, for a multi-candidate event in Orange City and to headline a fundraiser for Rep. Steve King, R-Iowa, before King endorsed Cruz.

4. The Iowa governor’s network

Team Christie leans hard on its associations with Iowa Gov. Terry Branstad, a Republican highly regarded by Christie’s target demographic. His aides tell Iowans that of the 58 “colonels” on Branstad’s 2015 inaugural committee, Christie has endorsements from 11; Bush from eight; Rubio, four.

They note that Branstad’s largest financial backer, Bruce Rastetter, has endorsed Christie.

Branstad’s two most recent campaign managers, Boeyink and Jake Ketzner, and his 2014 political director, Phil Valenziano, work for Christie’s Iowa campaign. Plenty of rumors exist that Branstad is a secret Christie backer, but Branstad is emphatic that he’s playing the role of impartial host to all the GOP contenders.

The governor “will remain neutral through the Iowa caucuses,” spokesman Ben Hammes said. But Hammes added that Branstad “has the utmost respect for Governor Christie, and they are personal friends.”

Branstad has shown an affinity for presidential hopefuls who are governors, including Texas’ Rick Perry before he dropped out.

On the campaign trail, Christie likes to tell the story about how Branstad called him on election night 2014 to boast that he won Lee County for the first time ever — and thanked Christie for helping him do it.

5. Other influential backers

Members of an important segment of the GOP say they’re doing as much as they can for Christie.

Rastetter is throwing a fundraiser for Christie Jan. 15 in West Des Moines. Tickets range from $250 to $2,700 a person.

6. Right words to backers of renewable fuel

Cruz, Iowa’s front-runner, has staked out a position in firm opposition to the renewable fuels mandate that many Iowa Republican leaders, including Branstad, say is vital to Iowa’s economic well-being.

Since the Iowa Agricultural Summit in March, Bush and Rubio have reshaped their answers into language that satisfies ethanol advocates, but Christie has been most straightforward in saying he fully supports the Renewable Fuel Standard. And he’s the only one of the three to tour an ethanol plant.

7. Buzz — he’s got it.

Since the most recent national GOP debate, Christie has built up his endorsement list to six state legislators — Bush has seven, Rubio six — and more than 70 other grassroots leaders.

“Chris Christie won’t win Iowa. (If he did, that’d be one heck of a shocker). But he could finish 3rd, then go to NH and win there,” Harry Enten, a political analyst with FiveThirtyEight.com tweeted Dec. 20.

Iowa politics watcher Kedron Bardwell, a professor at Simpson College, said the solid attendance at Christie’s Iowa events reflects a lack of consensus by mainstream Republicans on who is the best fit to challenge Cruz and Trump.

“There’s no concrete evidence of a Christie surge, other than the fact he’s making a concerted effort to spend more time courting Iowans,” Bardwell said. “But perception can also create reality, so if he can get the media to run with this narrative, it’s a boon to him in Iowa.”