The Brazilian Democratic Movement Party (PMDB) pulled out of the Latin American country’s ruling coalition this week, forcing President Dilma Rousseff to scramble for new allies ahead of an impeachment vote that could be called as early as mid-April.

The president would need 172 abstentions or votes in her favor in the lower chamber of Congress to survive an impeachment motion.

Vem Pra Rua, a civil society group, estimates that currently only 119 lawmakers are firmly on Rousseff’s side. Another 128 are undecided. Many of them are PMDB deputies.

The impeachment proceedings are the public face of what is really a political struggle to push Rousseff out. The formal case against the president rest on the allegation that she used an accounting trick to disguise a budget deficit in 2014, the year of her reelection — hardly the sort of offensive that would seem to require her ouster when there has been plenty of actual abuse of power to go around.

Kingmakers

Not the whole of the PMDB agrees it is time for Rousseff to go.

Michel Temer, the party leader and still Brazil’s vice president, has already outlined more business-friendly policies to help lift the country out of recession if he were to succeed her.

But just the other week, a PMDB deputy accepted the post of civil aviation minister while the party’s leader in the Chamber of Deputies, Leonardo Picciani, is considered pro-Rousseff.

The party’s divisions owe much to its lack of principle. The PMDB has no ideology. It exists rather to serve the interests of regional bosses and constituencies. It is better understood as a patronage network than a political party.

It hasn’t sought the presidency in decades and Temer has said he will not run for the post in 2018. The PMDB predictably backed the Social Democrats when they were the most popular before switching its support to Rousseff’s Workers’ Party in 2002 when her predecessor and mentor, Lula da Silva, won the election.

Ulterior motive

A PMDB-led interim administration would face many of the same problems that have bedeviled Rousseff, from an economy in free fall to a sprawling corruption scandal that is leaving virtually no party unscathed.

Indeed, many of the PMDB’s own members stand accused of corruption, leading some left-wing critics, including in Rousseff’s party, to allege that it seeks power to curb the investigation before it consumes them.