BUCHAREST (Reuters) - Lawmakers in Romania approved a bill on Wednesday that would cancel wiretap evidence used to prosecute past corruption cases and could wipe out hundreds of convictions, including that of the head of the ruling Social Democrats.

Social Democratic Party leader Liviu Dragnea reacts during an interview with Reuters, in Bucharest, Romania, May 23, 2018. Inquam Photos/Octav Ganea via REUTERS

The lower house vote, pushed through by the Social Democrats and their coalition partner, seemed certain to increase concern within the European Union whose executive on Tuesday criticized moves in Romania to weaken the independence of the judiciary and democracy.

If it comes into force, the bill would retroactively cancel evidence intercepted by the intelligence services on behalf of prosecutors based on court warrants.

It could nullify hundreds of verdicts for crimes ranging from corruption to human trafficking, including potentially the case against Social Democrat leader Liviu Dragnea, a former deputy prime minister.

Dragnea, who backed the bill together with Calin Tariceanu, leader of the junior coalition partner ALDE, was given a two-year suspended sentence in 2016 for electoral fraud and is currently on trial in a separate abuse of office case, with a third investigation under way.

Separately, prosecutors want to investigate Tariceanu in a graft case.

Some previous attempts by the ruling coalition in Romania to decriminalize graft offences, reduce sentences and bring magistrates under political control have failed and the opposition said it would challenge the bill in the Constitutional Court.

“Serious crime cases ... from 2005 onward could be reopened based on this bill, not just corruption, but also murder, human trafficking, drugs smuggling and so on,” lawmaker Stelian Ion of the opposition Save Romania Union told Reuters.

“They’re using a cannon to shoot at birds, and it could blow up the entire judicial system.”

He expected the Constitutional Court to reject the bill as it has done in similar cases in the past.

The European Commission, the U.S. State Department, thousands of magistrates and street protesters have criticized the government’s attempts to weaken the judiciary and raise the burden of proof.

The Social Democrats have shrugged off the criticism. They say the European Commission’s report on Tuesday which condemned developments in Romania, was unfair and politically-motivated.

Dragnea and Tariceanu, who are respectively speakers of the lower house and senate, have accused the intelligence service of abusing its power by faking evidence and illegally wiretapping millions of Romanians. Prosecutors deny the claim.