CHARLOTTE, N.C. – As President Bill Clinton gears up for his Democratic National Convention speech, it is hard not to notice that the former commander in chief’s support for President Barack Obama has become one of the most closely documented facets of the campaign.

But during the past year, Clinton has also involved himself in a number of House Democratic primaries, often taking sides in Member-vs.-Member contests generated by redistricting.

On this front, Clinton has a mixed record.

The former president is credited with making the difference for some of the candidates he endorsed in competitive primaries. But there were other races where his popularity and political prowess proved ineffectual.

However, Clinton did not appear to calculate a candidate’s viability when deciding whether to jump into a Democratic primary. Rather, those he endorsed had in common the quality of previously demonstrating loyalty to him and his wife, Secretary of State Hillary Rodham Clinton. Loyalty is the political quality the Clintons appreciate most, their allies say.

“He values it,” close Clinton ally James Carville said in an interview. “And if you helped his wife, he will help you. . He’s pretty up-front about it.”

In Member-vs.-Member Democratic primaries, the effect of Clinton’s endorsement was particularly acute.

Those who backed Hillary Rodham Clinton over Obama in the 2008 Democratic presidential primary found that they had an ally in Bill Clinton in 2012. Others, who went with Obama, saw that the popular ex-president actively working against them, often to devastating effect.

“I don’t know if it’s retribution,” Carville said. “I think it’s like, ‘There are so many things I can do, and I chose do it for the people who’ve helped me.’ I think it’s pretty straight-up.”

In several of the races, the candidates Clinton endorsed were able to overcome structural disadvantages to pull ahead on primary day.

Candidates used the Clinton endorsement in every way imaginable – highlighting the nod in radio and television advertisements, robocalls and direct mail. On occasion, the timing of his endorsement altered the trajectory of a race.

But in other instances, Clinton’s endorsement amounted to nothing, with the candidates he backed losing – in some cases big. As the primary season winds to close, Clinton had an even record: four wins, four losses and one outstanding race.

Arizona’s 9th: Aug. 28

Loss

Endorsed Candidate: Andrei Cherny

Ties to Clinton: Former White House staffer

This was the primary where Clinton’s support did not translate to a win when it might have.

Cherny was in a dogfight with two other Democratic stars in the race for this newly drawn tossup district.

Clinton endorsed in July, and Cherny advertised that endorsement to Democratic voters in every way possible.

In the end, EMILY’s List-backed former state Sen. Kyrsten Sinema and state Senate Minority Leader David Schapira were stronger, and Cherny finished in third place.

Minnesota’s 8th: Aug. 14

Loss

Endorsed Candidate: Former state Sen. Tarryl Clark

Ties to Clinton: Endorsed Clinton during the 2008 Democratic presidential primary

Clark had the backing of Clinton and EMILY’s List in her second bid for Congress earlier this summer. She and former Rep. Rick Nolan vied for the Democratic nomination to challenge Rep. Chip Cravaack (R) in a fall tossup race.

As much as the Clinton endorsement counted here, Nolan was able to rally the state’s Democratic establishment behind his campaign.

Connecticut’s 5th: Aug. 14

Loss

Endorsed Candidate: Dan Roberti

Ties to Clinton: Worked with Clinton ally Carville; father is a Clinton donor

A political newcomer, Roberti finished a distant third in the Democratic primary, following Clinton’s eleventh-hour endorsement. But the lateness of the support makes it hard to pin Roberti’s third-place finish to Clinton.

Carville backed Roberti early on and did much to help him on the fundraising front, which helped give the campaign legitimacy.

New York’s 18th: June 26

Win 

Endorsed Candidate: Attorney Sean Patrick Maloney

Ties to Clinton: Former White House staffer

Maloney was in a competitive Democratic primary to take on Rep. Nan Hayworth in the fall. Clinton, per usual form, endorsed his former staffer and performed robocalls.

At a time when the Wall Street Journal was calling into question Maloney’s resume, the Clinton endorsement offered the candidate political cover.

New Mexico’s 1st: June 5

Loss

Endorsed Candidate: Marty Chávez

Ties to Clinton: Endorsed Clinton during the 2008 Democratic presidential primary

In New Mexico’s open 1st district race, Clinton endorsed former Albuquerque Mayor, Chávez, who was involved in a competitive three-way Democratic primary. The endorsement came about four months before the June 5 primary, and then he did a robocall for Chávez with about three weeks to go. But the endorsement was not enough to help Chávez, and he finished well behind Bernalillo County Commissioner Michelle Lujan Grisham (who won) and state Sen. Eric Griego.

Chávez began the race as the favorite and with the highest name recognition. But he didn’t spend big on TV until the week before the primary.

New Jersey’s 9th: June 5

Win

Endorsed Candidate: Rep. Bill Pascrell

Ties to Clinton: Endorsed Clinton during the 2008 Democratic presidential primary

The odds were against Pascrell when it became clear that he and Rep. Steven Rothman were going to run against each other in the 9th district Democratic primary.

Rothman was an early Obama 2008 backer, while Pascrell was a Hillary man. Clinton’s endorsement of Pascrell seemed to blindside Rothman.

Up until just days before Clinton endorsed, Rothman insisted his loyal defense of Clinton during impeachment was enough to keep Clinton’s Pascrell endorsement at bay.

He was dead wrong. Clinton did not merely endorse, but he also made a personal appearance in the district.

Texas’ 16th: May 30

Loss

Endorsed Candidate: Rep. Silvestre Reyes

Ties to Clinton: Endorsed Clinton during the 2008 Democratic presidential primary

A double-shot endorsement from both Clinton and Obama could not save Reyes from his primary challenger, former El Paso City Councilman Beto O’Rourke.  

Clinton personally went to the El Paso district to campaign on behalf of Reyes and the incumbent still came up short.

Pennsylvania’s 12th: April 24

Win

Endorsed Candidate: Rep. Mark Critz

Ties to Clinton: Critz’s predecessor and former boss, the late Rep. John Murtha (D-Pa.), was a Clinton supporter in 2008.

The 2008 presidential campaign had a lot to do with Clinton’s decision to weigh in on the Member-vs.-Member primary between Democratic Reps. Jason Altmire and Critz. Altmire stayed neutral, despite much courting from Clinton. Critz benefited from the fact that his old boss, Murtha, had endorsed Clinton in that race.

Clinton has a history of playing well in Pennsylvania, and his nod was critical to Critz’s victory.

Maryland’s 6th: April 3

Win

Candidate: John Delaney

Ties to Clinton: Fundraiser for Clinton’s 2008 presidential campaign

When Maryland released its redistricting map, Delaney was not the establishment favorite.

State mapmakers drew new Maryland lines with a state legislator in mind.

And then the Maryland political world was stunned when Clinton endorsed unknown millionaire businessman Delaney. Overnight, Delaney gained instant credibility, and the race became his to lose.

His rival, state Senate Majority Leader Rob Garagiola countered with an endorsement from Gov. Martin O’Malley, but the momentum was set and the damage was done.

California’s 30th

Winner: To be decided in the fall

Candidate Supported: Rep. Brad Sherman

Ties to Clinton: Endorsed Clinton during the 2008 Democratic presidential primary

This is the lone outstanding race where Clinton has endorsed. After emerging from California’s jungle primary as the top two, Sherman and Rep. Howard Berman are running against each other for a second time, with the winner of the Nov. 6 contest set to return to Congress next year.

Clinton has not exactly endorsed Sherman, but he wrote Sherman a “letter of support” more than a year ago.

For now, Sherman has the edge, and Bill Clinton’s image has been squarely on his website for months.

Sherman backed Hillary Rodham Clinton in 2008.

Kyle Trygstad contributed to this report.