Updated at 9 a.m. Thursday with comments from Hegar and the DCCC chairman.

WASHINGTON -- Rep. Henry Cuellar, a Laredo Democrat, had breakfast on Tuesday with an embattled Republican colleague, Rep. John Carter.

But this wasn't just a friendly bipartisan chat over huevos or chorizo at San Antonio's Mi Tierra Cafe.

This was a campaign fundraiser for Carter, who is badly in need of cash as he fights for political survival against former Air Force combat pilot MJ Hegar. Ticket prices ranged to $2,700 and Cuellar didn't just attend. He also encouraged others to donate.

Congressmen cross party lines to write and pass bills, and Cuellar and Carter have worked together for years. But it's highly unusual for a lawmaker in one party to help a colleague from the other to keep his job. It's especially remarkable given that Democrats are angling for a "blue wave" potent enough to dislodge lawmakers who, like Carter, have held safe seats for years.

Hegar did not initially respond to requests for comment after Politico Playbook reported on Cuellar's unusual act of party disloyalty. On Thursday, Hegar vented to Texas Tribune, saying Cuellar had ignored her efforts to contact him earlier in the campaign.

""There's a difference though between the friendship that belongs on the golf course and the fighting for our ideals and our values on the battlefield," she said at a Tribune event, adding, "I think it's not actually an example of bipartisanship. I think it's actually an example of what's wrong with politics today... It's a little bit of a little boys club maybe."

So, if she wins, those Democratic delegation meetings might be a bit tense.

MJ Hegar more on Henry Cuellar: "It's an example of what's wrong with politics. A little boys club, maybe." — Abby Livingston (@TexasTribAbby) September 13, 2018

Rep. Ben Ray Luján, D-N.M., chairman of the Democratic Congressional Campaign Committee, said Thursday morning that the party's House campaign arm encourages incumbents to support all of its nominees.

"I am supporting MJ," he said at a sit-down with regional reporters at Democratic headquarters near the Capitol. "I've been clear to all of our colleagues, including my friend Mr. Cuellar, that I think MJ is going to win this district.... That's definitely a race to watch."

Through an aide, Cuellar said that his help for Carter doesn't imply an endorsement.

"The congressman hasn't taken any kind of position on that match-up," said Cuellar adviser Colin Strother. "He and Judge Carter have a long history of working together. Judge Carter has co-sponsored 16 of our bills and we have co-sponsored 13 of his bills. The congressman is a member in good standing [of the DCCC] and has not only paid his entire dues for this Congress but he is also advanced his dues for the next Congress."

But dismay on the left was readily apparent.

"Sadly, this is far from out of character for Cuellar," wrote the liberal Daily Kos, which noted that Cuellar votes with President Donald Trump more than any Democrat in Congress.

It's a centrism he has long touted.

Only four members of the House scored higher on bipartisanship in 2017, according to an analysis from The Lugar Center and Georgetown University McCourt School of Public Policy.

As a member of the Texas House, he supported then-Gov. George W. Bush for president in 2000. Bush's successor, Rick Perry -- now the energy secretary -- named him secretary of state, Texas' chief election officer and the governor's emissary on Mexico and border affairs.

Because of his bipartisanship, or despite it, Cuellar remains popular in his district -- a Democratic stronghold that picked Hillary Clinton over Trump 58-38 in 2016, and Barack Obama over Mitt Romney 60-39 four years earlier.

Carter's district, which straddles the I-35 corridor from Round Rock to Temple and includes part of Fort Hood, is a near mirror image: Trump beat Clinton 54-41, and Romney topped Obama 60-38.

Carter spokesman Bruce Harvie said the congressman, a former trial judge, is grateful to Cuellar for attending the event.

"The congressmen have a long friendship and share a strong belief in the power of bipartisanship. Judge Carter believes bipartisan relationships are especially important given the current climate in Congress. He's honored to call Rep. Cuellar a friend and colleague and enjoys working with him for the betterment of all Texans," he said by email.

As The Dallas Morning News has documented, Cuellar has a long history not just of bipartisan cooperation but of going out of his way to provide political aid to members of the other party.

During the Obama administration, Cuellar was a vocal critic of the Democratic president's handling of border security, and teamed up with Republicans to streamline the process of deporting people caught in the country illegally.

He has continued to work toward that goal in the Trump era, though he is hardly lockstep with the current president. Like other Democrats, he has been deeply critical of Trump policies on a border wall and on blowing up a free trade deal with Mexico and Canada.

"Although I was not a host of the event, I was honored to attend as I typically do for colleagues who visit my district. Judge Carter is a dear friend and trusted colleague with whom I work on Appropriations. He is knowledgeable and supportive of issues important to South Texas. In today's climate, more than ever, friendship is more powerful than partisanship," Cuellar said in a statement provided by his campaign.

Carter touts his support for the border wall.

John Carter supports strengthening the border and passed legislation to provide $1.6 billion to begin construction on a wall along America’s southern border with Mexico. pic.twitter.com/IGHhlHZlxL — John Carter (@JudgeJohnCarter) September 5, 2018

It's not clear how much tangible help Cueller provided by encouraging attendance at Tuesday's breakfast.

But Carter is much in need of cash. Midyear campaign finance reports showed him lagging badly, having raised just under $1 million to Hegar's $1.6 million, and with $538,000 in the bank compared to her $867,000.

As far as Cuellar's own history of donations, he's a loyal Democrat. He ran unopposed in the March primary and faces no Republican in November, only Libertarian Arthur Thomas IV.

In the last decade, his leadership committee, Texas First PAC, has given out $135,000, all to Democratic candidates. Most were running for Congress, though $5,000 went to Hillary Clinton's presidential effort in 2016.

Hegar has collected an unusual amount of cash and exposure for a challenger in a district that, on paper, isn't all that competitive.

More than 5 million viewers have seen a three-minute ad she released in June. It recounts a childhood marred by domestic abuse, a career as a decorated Air Force pilot, and her push to end the military's ban on combat roles for women.

Hamilton playwright and actor Lin-Manuel Miranda hailed it as the "best political ad anyone's ever seen."

As a combat pilot in Afghanistan, she received a Purple Heart after her helicopter was shot down. A campaign video issued last week -- the press release called her "Badass Democratic Candidate MJ Hegar" -- focused on her decision to hide the scars with tattoos.

"When I took a round through my helicopter windshield, the bullet fragmented across my arm and leg....I used these tattoos to cover the scars. I approved this message, so our families can be covered -- with health care they can actually afford."

Carter's campaign message has not gone viral.

Democrats have identified three GOP incumbents as their top targets in Texas -- Dallas Rep. Pete Sessions, Houston Rep. John Culberson and San Antonio Rep. Will Hurd. Carter hasn't been seen as nearly as vulnerable as those three. Some independent handicappers have ranked the race as one to watch. Others haven't listed it as anything but solid Republican.

Carter and Cuellar serve together on the Appropriations committee, which controls hundreds of billions in spending. Carter chairs the subcommittee on military construction and veterans affairs.

That's a strong bond. There's an old joke that Congress actually has three parties: Democrats, Republicans, and appropriators.