Former House majority leader Eric Cantor, right, campaigns with Republican presidential candidate Jeb Bush in Norfolk. Cantor endorsed Bush on Thursday. (Jay Westcott/Reuters)

Sinking in the polls amid the rise of renegade party outsiders, Jeb Bush is turning to something not in style this summer: establishment support.

The Republican presidential candidate has accumulated pledges from a steady trickle of mayors, state legislators, former governors and about two dozen members of Congress in recent weeks, including former House majority leader Eric Cantor on Thursday.

The tally puts Bush ahead of other 2016 contenders in racking up endorsements but far behind previous GOP candidates at this point in a presidential campaign cycle. The size of the Republican field, plus the sustained dominance of flamboyant businessman Donald Trump, is causing many to refrain from picking sides.

Bush began the year as the GOP’s presumed front-runner, but his poll numbers plunged into the single digits in a national survey this week alongside the rise of Trump and former neurosurgeon Ben Carson, who have pushed ahead of elected officials in the field.

To many Republicans, including Trump, Cantor’s endorsement of Bush seemed an odd choice. Cantor was defeated by an upstart tea party challenger in a GOP primary last year, plunging House Republicans into chaos.

Jeb Bush speaks at a town hall meeting in Norfolk. His support fell into the single digits in a poll released this week. (Jason Hirschfeld/AP)

“Who wants the endorsement of a guy (@EricCantor) who lost in perhaps the greatest upset in the history of Congress?” Trump tweeted.

Campaigning with Bush in Norfolk on Friday, Cantor acknowledged that Trump “talks about the kind of things that strike the anger in people.”

But he told reporters: “We’re at a turning point as a country; we’re at a turning point for our party. It is time for the Republican Party to unite around strong conservative principles that Jeb Bush has stood for in Florida.”

Over the course of several weeks, Bush has been assembling state leadership teams, most of them led by prominent pols and filled out with lower-tier politicians.

In Virginia, Cantor is co-chairing the Bush campaign along with Kay Coles James, a former state health secretary, and John Hager, a former lieutenant governor and chairman of the Republican Party of Virginia. Hager’s son Henry is married to Bush’s niece Jenna Bush Hager, daughter of George W. Bush.

In the states holding the earliest contests — Iowa, New Hampshire, South Carolina and Nevada — elected officials usually avoid endorsements in order to promote competitive races. So Bush is recruiting current or former county or state party leaders, school board members, small-business owners, and former supporters of his father or brother.

Of the four early-voting states, he’s amassed the most establishment support in Nevada, where Sen. Dean Heller and Rep. Mark Amodei endorsed him this month.

“Jeb had an interest in Nevada,” said Bush supporter Paul Anderson, the majority leader in the Nevada Assembly. “He came several times, he met with several of us. He extended a request and was very personal in that request. It wasn’t through surrogates or any other way.”

In Georgia, which holds a critical March 1 primary, Lt. Gov. Casey Cagle and Attorney General Sam Olens are backing Bush. In Michigan, Attorney General Bill Schuette — who worked for Presidents George H.W. Bush and George W. Bush — is on board, along with six state lawmakers and other officials from the two Bush administrations.

At this point in previous presidential campaign cycles, however, the eventual Republican nominees enjoyed more widespread establishment support, according to an analysis by FiveThirtyEight.com, a nonpartisan polling and statistics site often cited by presidential campaigns.

Using a system that doles out points based on endorsements from members of the House and Senate or sitting governors, the site puts Bush atop the GOP field, ahead of New Jersey Gov. Chris Christie, former Arkansas governor Mike Huckabee and Sen. Rand Paul (Ky.). No sitting governor has endorsed Bush, but he has the support of at least 22 lawmakers, including Heller and Sens. Orrin G. Hatch (Utah) and Susan Collins (Maine).

House Speaker John A. Boehner (R-Ohio) is friendly with Bush and publicly urged him to consider running, but he isn’t expected to endorse any candidate, given his leadership perch. A handful of former senior House aides — including former Boehner spokesman Michael Steel and Robert S. Karem, a onetime top policy adviser to Cantor and his successor as majority leader, Rep. Kevin McCarthy (Calif.) — are now top Bush campaign advisers.

Rep. Adam Kinzinger (Ill.) was among the first Republicans in the country to endorse Bush and said he knows of several colleagues who are withholding support for him given the fluidity of the race.

“With 17 candidates, that’s totally understandable,” said Kinzinger, who predicted that Bush will quickly amass more endorsements as the field narrows.

But the resistance to Bush among many establishment Republicans is telling. Rep. Peter T. King (N.Y.) — the kind of hawkish, law-and-order lawmaker whom Bush should be able to win over — said he’s likely to support Bush, but not yet.

“All things being equal, I will endorse Jeb Bush, the way it looks now,” he said in an interview. “But I have to see if he can sustain a campaign. He has the financial resources and the organization in place, but it’s a long way from now to January.”

Jenna Portnoy in Norfolk contributed to this report.