It has been an open secret for some time that one of the weakest elements of the extended Democratic Party family under President Obama has been the Democratic National Committee. This neglected institution has become a public embarrassment on the eve of a national convention designed to highlight party unity.

The cascade of internal DNC emails released Friday by WikiLeaks underscore what Sen. Bernie Sanders and his advisers have long claimed: The DNC appeared to have its finger on the scale for rival Hillary Clinton through the long nominating contest.

In some ways, that is not entirely surprising, because Clinton is the institutional choice of the Democrats and because DNC members are the party’s establishment. But the national committee’s role is to maintain strict neutrality during the primaries, and the emails indicate that did not happen.

The emails also paint a picture that confirms what has long been assumed, that of a DNC more or less isolated from key elements of the party — including the White House — and left to the devices of Rep. Debbie Wasserman Schultz (Fla.), its long-standing chair. Her swift resignation, under pressure from Clinton’s team, will help move her out of the way, but the potential for more embarrassing emails being released this week and beyond remains.

Clinton did not win the nomination because of nefarious help from the DNC. But there always were questions about the DNC’s leanings. A small example was the debate schedule. Whether because of outright favoritism toward Clinton or something else, the schedule — limited in number and out of sync with many of the early primaries and caucuses — was considered initially more helpful to Clinton than her challengers.

Debbie Wasserman Schultz, the chairwoman of the Democratic National Committee said she will resign this week in the aftermath of the release of thousands of internal email exchanges among Democratic officials. (Thomas Johnson,Monica Akhtar/The Washington Post)

Wasserman Schultz denied it, and she said correctly that those Saturday night debates came at the demands of the major broadcast networks. But after seeing what was being said about Sanders in some of the emails, the senator from Vermont and his advisers have concluded that Wasserman Schultz and others were quietly cheering for Clinton. Sanders has every right to feel aggrieved.

But this is more than an issue of whether Sanders got fair treatment in this campaign. The problems at the DNC date back years. Instead of being dealt with by those who had the power to do so, they were left to fester.

Obama came to the presidency without deep ties to the institutions of the party. He owed few people much and liked it that way.

During the first two years of his presidency, the DNC was used to develop and test some of the infrastructure — data collection, analytics and modeling techniques — that allowed them to jump-start the work of his 2012 reelection committee.

Although it took all of 2011 and much of 2012 to perfect those tools (they weren’t always perfected), the reelection team had a running start because of what was funded through the DNC.

Other than that, the Obama political operation has been largely separate and free-standing, through various committees with the initials OFA — Obama for America, Organizing for America, Organizing for Action, etc. The DNC had to compete for money with those Obama-linked organizations.

(Spencer Platt/Getty Images)

Also, it was not until the summer of 2015 that the Obama committees’ information was fully shared with the national committee. My colleague Juliet Eilperin recently reported that in 2010, at a meeting of Democratic governors, one governor asked an administration official, “Will the OFA please join the Democratic Party.”

The president did little about the conditions at and leadership of the national committee. He helped raise funds, but overall, the DNC’s fundraising has trailed that of the Republican National Committee. According to data from the campaign-finance watchdog OpenSecrets, the DNC has raised $128 million this cycle, compared with $181 million for the RNC. The party that holds the White House should do better than that.

Given her role, Wasserman Schultz has been one of the most visible faces of the party, a frequent guest on cable television who has delivered the party’s talking points about the opposition with robotic discipline. But she has been a controversial chair, with Democrats privately questioning her effectiveness as a spokeswoman and a party builder. The email leaks turned that into a public conversation.

On Sunday morning, Sanders called on her to resign. Others followed, and by mid-afternoon she issued a statement saying she would step down after the convention. As such controversies go, it was resolved relatively swiftly. But it was hardly a full resolution of the issue and raised the question of why it came to this before action was taken.

There have been private complaints about Wasserman Schultz for a long time. She is no favorite of Democratic congressional leaders, who earlier this year floated the possibility that she could be moved aside before the election. It did not happen, in part because it could not easily be done unless she was willing to go.

Clinton’s team has long known that Wasserman Schultz was an unpopular chair. But the feeling inside the Brooklyn campaign headquarters was always that her removal was not worth the time, effort or public brouhaha that would result.

The Clinton campaign always had bigger issues to deal with, such as winning the nomination against a stronger-than-expected challenge from Sanders and now dealing with Donald Trump, an opponent who plays by new rules. Worrying about the chair of the party through all this seemed like a small-bore problem. The team was always content to let things go through the duration of the campaign.

The Washington Post reported in June that Russian government hackers penetrated the DNC’s computers and stole opposition research about Trump. Making the rounds of the Sunday morning political talk shows, Robby Mook, Clinton’s campaign manager, said experts informed the campaign that the email leak was the work of Russians trying to help Trump. The timing of the leak certainly seems more than coincidental, and that leaves open the possibility that more material is to come.

The leak left Wasserman Schultz in an untenable position at the start of a convention that she and the DNC have been planning for many months and in which she would have been a highly visible presence. Only a day earlier, she was one of the speakers at the rally in Miami where Clinton unveiled her running mate, Sen. Timothy M. Kaine of Virginia. Now she will be mostly in the background and then gone as chair of the party.

Clinton cares more about party-building and party institutions than Obama does. She made it part of her campaign appeal as she worked to gain support of state party officials and other superdelegates during the primaries. As president, she would probably restructure the committee and probably would have brought in her own person as chair to run it.

That timetable was accelerated by the WikiLeaks dump. For the Democrats, it’s ironic that a long-standing problem that could have been dealt with before has emerged as a disruptive force at a moment of maximum visibility.