WASHINGTON (CNN) -- Mark Penn's decision to step down as Hillary Clinton's chief strategist comes after months of bitter campaign infighting over disappointing performance and questionable judgment.
Mark Penn will continue to advise Hillary Clinton's presidential campaign.
Pennsylvania Gov. Ed Rendell, a Clinton campaign surrogate, told NBC's Meet the Press Sunday that there were a "lot of issues" which might call for the senior adviser's resignation.
Penn was widely criticized after acknowledging Friday he had met with the Colombian ambassador to the United States earlier in the week to discuss the pending U.S.-Colombia trade pact, which Clinton has criticized on the campaign trail.
Penn said he was meeting on behalf of his public relations firm.
In the days between the first reports of that session and his resignation Sunday night, Penn was conspicuously short of defenders from the Clinton camp, some of whom had been openly anxious to see his exit for months.
The dynamic within the campaign had devolved to the point where senior staffers got into shouting matches with Penn, all sides hurling profanity at each other in exchanges that made their way into news accounts.
Penn, who had guided former President Bill Clinton's re-election bid to victory in 1996, was serving as both chief strategist and chief pollster -- an unusual dual role that translated into million-dollar paydays some months. Watch what the resignation could mean for Clinton »
Drawing even more grumbling from within the Clinton team: Penn never gave up his day jobs as CEO of public relations giant Burson-Marsteller and president of Penn, Schoen and Berland, his political consulting firm. Senior Clinton advisers derided him publicly -- both anonymously and openly -- after Clinton fell short in Iowa.
Despite the complaints, the Clinton camp did not completely cut ties with Penn. He will remain as an adviser on a daily basis and his firm will continue to conduct polling for the campaign.
Penn's strategy, which emphasized Clinton's experience, toughness and inevitability, was heavily debated within the campaign, with many supporters blaming it for Barack Obama's emergence as the candidate of "change." This approach met stiff resistance from other aides, who said voters were instead looking for hints of warmth from Clinton.
Penn also pushed the "big states" strategy that essentially ceded smaller states and caucuses to Obama. Some say this enabled the huge victory margins that translated into what is now a nearly-insurmountable pledged delegate lead for Obama.
After Clinton didn't do as well as she hoped on Super Tuesday -- a date when staffers had long predicted she would virtually wrap up the nomination -- campaign senior adviser Harold Ickes told the New York Observer that Penn's claim that he did not bear responsibility for her performance didn't hold water, and that the strategist was "the single most responsible person for this campaign" besides the candidate herself.
But after Clinton bounced back with strong showings in Ohio and Texas on March 4, some staffers insisted Penn did not deserve the credit for those victories.
Like Patti Solis Doyle -- another longtime Clinton adviser who kept her post as campaign manager despite harsh criticism within the ranks -- Penn stayed on for months as the internal discord became a constant theme in campaign coverage.
His departure followed the same arc as Solis Doyle's: Clinton was reluctant to cut ties to the longtime loyalist, despite persistent grumbling from some of her team over lackluster campaign performance.
Donors began to complain loudly, followed by the hiring of a replacement -- ostensibly in an advisory role. In Penn's case, Democratic pollster Geoff Garin was brought in to plot long-term strategy along with communications director Howard Wolfson. Finally, a crisis moment led to a transition from leadership to an "advisory role."
Penn and his political consulting firm will continue to advise the New York senator's Democratic presidential bid, but Penn will give up his job as chief strategist, campaign manager Maggie Williams said.
Penn called his meeting with the Colombian ambassador "an error in judgment that will not be repeated," and apologized. That prompted Colombia's government to fire the company Saturday, calling the remarks "a lack of respect to Colombians."
Penn said Friday that Clinton's opposition to the U.S.-Colombia pact, which the Bush administration is trying to push through Congress, "is clear and was not discussed" during his meeting with the ambassador. And Clinton spokesman Mo Elleithee said Penn's meeting was "not in any way done on behalf of the campaign."
Clinton did not answer reporters' questions about Penn's exit during a campaign stop in New Mexico on Sunday.
Sources in the Clinton campaign said Penn realized this weekend he needed to step aside, and Clinton was disappointed he met with the Colombians.
Clinton's campaign paid Penn, Schoen and Berland more than $6 million by the end of February and owed the firm $2.5 million, according to her campaign finance reports. E-mail to a friend
CNN's Candy Crowley contributed to this report.