FILE PHOTO: Armed Forces members patrol in Jacarezinho slum during an operation against drug gangs in Rio de Janeiro, Brazil January 18, 2018. REUTERS/Ricardo Moraes/File photo

BRASILIA (Reuters) - Brazil’s political affairs minister Carlos Marun said on Monday that passage of a bill to overhaul the country’s costly social security system has effectively ground to a halt in Congress and would become a campaign issue in this year’s election.

Marun spoke to reporters after the head of the Senate, Eunicio Oliveira, said the federal government’s military intervention in Rio de Janeiro would, by the rules of the country’s constitution, block any vote on pension reform or any other measure requiring a constitutional amendment.

But Marun acknowledged what President Michel Temer’s critics believe is the real reason for holding up a pension vote: the unpopular bill never gained enough support and the government faced certain defeat.

“We don’t have the votes. I couldn’t guarantee we would have the votes by the end of February,” he said. That was the government’s deadline for passing the bill before lawmakers turned their attention to securing their seats in the October general election.

Pension reform is the cornerstone policy in Temer’s efforts to bring a bulging budget deficit under control. Generous pension benefits and early retirement have turned social security into the main driver of a deficit that cost Brazil its investment grade.

Marun, the cabinet minister charged with mobilizing coalition support in Congress, said pension reform would become a key issue in the election campaign if Congress did not take it up again.

The legislation to streamline social security, which required amending the constitution, was lined up for a first vote in the lower house of Congress this week.

But on Friday the government ordered the army to take over command of police forces in Rio de Janeiro state in a bid to curb violence driven by drug gangs, an intervention that blocks any constitutional changes during its duration.

Temer decreed the Rio intervention through Dec. 31, his last day in office.