How the ‘secret budget’ in Congress harms the party system

A group of lawmakers from the center-left Workers’ Party exhibited some odd behavior in two crucial votes last week. First, Senator Rogerio Carvalho voted in favor of a resolution to keep records of opaque budgetary grants a secret, and then a majority of Workers’ Party senators sided with the Bolsonaro government on a budget-related bill. The next day, Workers’ Party chair Gleisi Hoffmann cut a bemused figure on CNN. “I didn’t understand a thing,” she said.

And Ms. Hoffmann is not alone. Several political pundits noted the peculiarity of the votes, which benefited the Jair Bolsonaro administration and the group of conservative rentier parties known as the “Big Center.” Beyond the obvious ideological differences between the Workers’ Party and the government, the group is expected to coordinate the opposition against Mr. Bolsonaro in next year’s elections.

The behavior is even more puzzling when one considers that the Workers’ Party is supposed to be Brazil’s most institutionalized and programmatic political party. In other words,...