Ecuadoreans have voted to scrap unlimited presidential terms, a move which should stop leftist ex-leader Rafael Correa from returning to power.
With almost all votes counted, 64.3% of voters backed a constitutional change which will prevent presidents from holding office for more than two terms.
The question was one of seven being put to voters in a referendum.
It was called by current President Lenín Moreno, once Mr Correa's deputy but now his staunch opponent.
The questions also include a proposal to bar officials convicted of corruption from politics.
Mr Correa split very publicly from Mr Moreno, who took office in May 2017 after winning an election as the candidate of Mr Correa's Alianza Pais (Country Alliance) party.
The referendum was Mr Moreno's way to "distance himself from his predecessor and consolidate his political process", said Ecuadorean news and analysis portal GK.
Voters also gave broad backing to measures to limit the mining of minerals in environmentally protected areas and to end the statute of limitations for sexual crimes against minors.
Some of the measures will require approval by Congress.
Mr Moreno, 64, was disabled in a 1998 armed robbery and is currently the only serving head of state using a wheelchair. He was Mr Correa's vice-president between 2007 and 2013.
So this is a battle over Mr Correa's legacy?
Yes - and a deeply personal one.
Mr Moreno wants a decisive vote to mark an end to the Correa-era "Citizens' Revolution" and close the door to Mr Correa's candidacy in the 2021 election.
"Corruption sets in when you have only one government that thinks it will stay on forever," he said on the campaign trail this week, according to Reuters news agency.
But Mr Correa has called his former ally a "traitor" and said he was "trying to destroy everything that has to do with Correa", the agency reports.
Mr Correa, who in January 2018 returned from Belgium where he had been living to spearhead the "No" campaign, has called the referendum a "coup d'état".
He accuses "the right" of wanting to "invent a crime against me to disable me", said AFP news agency, referring to a referendum measure to bar those convicted of corruption from politics.
Jorge Glas, vice-president to both Mr Correa and Mr Moreno, was sentenced to six years in jail in December 2017 for his involvement in a case of bribes paid by Brazilian firm Odebrecht.
Mr Correa has not himself been convicted of any corruption. He has voluntarily agreed to testify in court on Monday as prosecutors investigate allegations of irregularities in oil sales to China and Thailand during his time in office.