The Liberal Democrats have been accused of failing to stick up for women after Lord Rennard had his suspension from the party lifted.
The party's former chief executive has been brought back into the fold after disciplinary action linked to allegations he pestered women was dropped.
In a statement, the peer said he was "pleased" with the outcome, stressing that none of the claims against him had been proved.
But former Lib Dem activist Susan Gaszczak, an alleged victim who resigned her membership in July over the failure to expel him, said the party lacked "backbone".
And Labour insisted that Nick Clegg was obsessed with protecting the Lib Dems' electoral prospects rather than showing "leadership" on the issue.
After police dropped their probe into Lord Rennard's behaviour towards female activists, Alistair Webster QC was drafted in last year to produce an independent report.
He concluded that although the evidence against the peer was "broadly credible", wrongdoing could not be shown beyond reasonable doubt.
Mr Webster urged the peer to "reflect upon the effect that his behaviour has had and the distress which it caused and that an apology would be appropriate".
However, Lord Rennard refused to say sorry immediately - arguing that he had not even been allowed to see the full version of the QC's report.
He was suspended pending disciplinary action for bringing the party into disrepute with his response to the investigation.
It was not until May that Lord Rennard paved the way for his reinstatement by conceding he may have "inadvertently" encroached upon "personal space", saying he wanted to "apologise sincerely for any such intrusion".
A Lib Dem spokesman said: "The Regional Parties Committee met this week to consider whether the party had been brought into disrepute by statements made by Lord Rennard, or on his behalf, following the publication of Alistair Webster's conclusions.
"It decided not to proceed with the disciplinary process against him.
"This brings the matter to a close and means the suspension of his membership is lifted."
In a statement, Mr Clegg insisted the "party has changed" and signalled his desire to reduce the burden of proof in disciplinary cases from criminal to civil.
"The Liberal Democrats have taken a long, hard look in the mirror since these allegations were made last year and I am confident that the party has changed," the Deputy Prime Minister said.
"It is clear that a number of women in our party felt let down that the party failed to act on their complaints appropriately. I am determined that no member of our party should find themselves in that position again.
"That's why I immediately appointed Helena Morrissey to carry out a root and branch review of our culture and processes and made sure we acted on her recommendations.
"In addition, at my request the Party President and the Federal Executive established a review into our procedures for handling cases such as this to ensure that the party's rules are fit for purpose in the future.
"This review has now been completed by a senior barrister who has recommended that we make changes to the current criminal burden of proof and these changes will now be taken forward."
Party president Tim Farron said: "We have changed our rules and codes of conduct at every level, from grassroots members to parliamentarians so that everyone involved in the party is aware of their rights and responsibilities.
"We have changed how complaints are reported and addressed, and we have appointed a Pastoral Care Officer to help and advise those making a complaint.
"No one should ever have to feel that their concerns are being dismissed or ignored and I am clear that the Liberal Democrats should become the 'gold standard' for how voluntary organisations treat their members and staff."
Lord Rennard said: "I am pleased that all disciplinary investigations against me have been brought to an end and that the suspension of my party membership has been lifted.
"This has taken a long time... All allegations made about me have now been investigated thoroughly, including by the Metropolitan Police, and fell at the first hurdle as to whether or not there was sufficient evidence to proceed further.
"The English Appeals Panel confirmed in July that I could not be criticised over my reaction to the previous report by Alistair Webster QC, as I was not given sight of the report for 11 weeks.
"The worst that might be said of me in that report was that I may have inadvertently encroached on the personal space of some of the complainants, and I apologised for this to all four of them.
"I remain a committed member of the Liberal Democrats and a strong believer in the principles of the party, as set out in the constitution, and based on the values that led me to join the Liberal Party in my teens."
Former Lib Dem MEP Chris Davies said Lord Rennard's treatment had been "outrageous" and he had been portrayed as a "pantomime villain".
"I think the way in which Chris Rennard has been treated is outrageous, absolutely outrageous," he said.
"This man has been singled out and pilloried for month after month. It has been like the Salem witch trials."
But Ms Gaszczak said: "The party democracy obviously has no moral compass.
"They say we are credible, then fail to act on it and don't see the impact this has on women and women voters."
She said she did not blame Mr Clegg, saying his "hands were tied" due to the party's rules.
"I don't blame Nick for this," she said.
"This is purely down to the English party and their rulings."
Labour's spokeswoman for women and equalities, Gloria De Piero, said: "Nick Clegg has sent a clear message to women voters - he is more interested in trying to salvage the Lib Dems' fading election hopes than do the right thing by the women who made these serious complaints.
"Yet again he has failed to show any kind of leadership."
Ms Gaszczak said she had been assured that Lord Rennard would not play a role in the party's election campaign, but warned other women would follow her lead in resigning their Lib Dem membership.
She told BBC Radio 4's Today programme: "It seems to be one fudge after another fudge and it's ended up with myself and two of the other women leaving the party and there's just one of us who is still a member."
Asked if the Lib Dems had a "woman problem", she said: "I think that they do and I think they have a more serious one now and I don't see how they are going to come back from this easily.
"The number of women last night that were getting in touch and saying 'I'm going to resign from the party now' - and I was telling them to sleep on it to make sure it's the right decision for them - was astounding."
She said Mr Farron had sent her a text message to say that Lord Rennard would not play a role in the party's election campaign, adding: "I have had assurances privately that that would not be the case.
"I had a text message from the party president last night and they have said under no circumstances will he be advising the party."