Senedd members voted to scrap plans for gender quotas in Welsh Parliament elections despite concerns about "false hope" and taxpayers' money being wasted.
Labour, Plaid Cymru, Liberal Democrat and Conservative politicians all raised concerns about the Welsh Government's abandoned plans to ensure half of candidates are women.
Joyce Watson was deeply disappointed, warning that the gender quota bill was introduced while it was questionable whether the Senedd had the necessary powers.
The Labour backbencher said: "I will ask the government in future – any government in future – not to do what I believe we've done and that is: raise false hope."
Describing the u-turn as shameful, Plaid Cymru's Sioned Williams criticised Wales' first female first minister for "binning the very bill that would ensure women have an equal voice".
Jane Dodds, the Lib Dems' leader in Wales, was similarly bitterly disappointed, saying: "We spent time, we spent money, and it's just been thrown down the drain."
'Futile'
Darren Millar, the Conservatives' shadow constitution minister, told the Senedd his party has never had a problem with the aim of improving diversity.
"We have had a beef as to the means to achieve that," he said, arguing the bill was outside the Senedd's powers and criticising the focus on one element of diversity.
Mr Millar pointed to a YouGov poll that showed people in Wales opposed gender quotas as he raised concerns about spending on the "futile" legislation.
He said: "It is very, very disappointing that millions of pounds – and it is millions of pounds – and lots of time, lots of energy has been spent."
Mr Millar, who represents Clwyd West, added: "I'm pleased to see the back of this legislation. I hope it never returns because we don't have the competence to deliver it."
'Historic'
Heledd Fychan warned Wales' democracy will suffer as she emphasised Plaid Cymru's disappointment at the Welsh Government for "turning its back" on the bill.
She said the first gender-balanced Senedd in 2003 received international attention, stressing that the same parity has not been achieved in the 21 years since.
Ms Fychan told the debating chamber or Siambr: "For the first time in our history, a first minister who is a woman – an important milestone in this Senedd."
"But how disappointing to see that one of the first actions of the government led by the new first minister is to withdraw a bill that would help other women to achieve that same role."
Accusing ministers of lacking ambition, she said: "This isn't good enough. This bill would have made a positive difference...it would have been a historic step."
'Blood on the floor'
Labour's Julie Morgan said it was a shame to see reforms shelved.
"When the Senedd started, in the Labour Party, we had a twinning exercise," said the Cardiff North MS. "There was blood on the floor but it was very successful and we have consistently since then...had more women than men in our group."
Sian Gwenllian, who chairs the cross-party group on women, warned that creating a Senedd without equality at its heart in legislation is a serious error.
"It is an unacceptable sign that gender equality, somehow, doesn't matter," she said.
Former Plaid Cymru leader Adam Price described the moment as profoundly depressing, claiming the UK and Welsh Labour are at loggerheads.
He suggested the UK party would not support an order, under section 19 of the 2006 Government of Wales Act, to bring the bill within the Senedd's scope.

'What changed?'
Jane Hutt, the member in charge of the bill, which was delayed four years before being scrapped, urged political parties to take voluntary steps to ensure equal representation.
Pressed by Senedd members asking "what changed?", she said ministers reflected over the summer on the difficulties of passing the bill before the next election in 2026.
The social justice secretary told the Siambr that the Elections and Elected Bodies (Wales) Act, which was passed this year, will improve diversity in Welsh politics.
Reiterating calls for positive action, Ms Hutt, who was first elected in 1999 as the Vale's MS, said she did not think she would be a Senedd member today had it not been for Labour's twinning process.
Senedd members voted 40-12 to withdraw the bill.

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