"(President Luiz Inacio Lula da Silva) should announce he is no longer a candidate for re-election," said Cardoso.
The ex-president admitted, however, that Lula has apparently not been that adversely affected by an ongoing scandal, as his approval rating remains high.
Earlier this month a federal lawmaker accused the Lula administration of offering kickbacks to congressmen for their support on key votes.
Lula has denied the allegations and his accusers have yet to provide any concrete evidence of wrongdoing.
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