Brazilian President Dilma Rousseff faces threat of coalition implosion

Brazilian President Dilma Rousseff could see her coalition disintegrate this week amid a political crisis that threatens to topple her government, as a congressional committee ponders impeachment proceedings against her.

Already the Brazilian bar association has said it will file a new request today to Congress for her impeachment.

But Rousseff's real troubles begin on Tuesday, in the capital of Brasilia, when her major coalition partner, the centrist PMDB party, will in all likelihood formalize its break with her government.

The PMDB, which has 69 deputies and is the biggest party in Congress, is led by Vice President Michel Temer, who would serve out the rest of Rousseff's term if she is impeached, until the winner of the 2018 presidential election takes office.

The 75-year-old politician has not done so much as lift a finger to defend the president in recent weeks, even as her impeachment proceedings unfolded against a backdrop of deep recession and mass protests.

Instead, he met last Monday with opposition leader Aecio Neves, who narrowly lost the 2014 election to Rousseff, to discuss the future of the nation.

Since the beginning of March, millions of Brazilians -- especially those skewing whiter, wealthier and better-educated, who are clustered in the megacities of Brazil's southeastern industrial corridor -- have marched to demand Rousseff's ouster. Her backers from the left have held their own demonstrations, with much smaller crowds.

According to O Globo newspaper, 80% of PMDB's leadership members could vote in favor of a break from the coalition.

And other parties could follow suit, including the Progressive Party (PP), which has 49 deputies.

The impeachment case is based on accusations that Rousseff doctored the government's accounts to boost public spending during her 2014 re-election campaign and hide the depth of a recession last year.

With her coalition splintering, Rousseff called her predecessor and mentor, former president Luiz Inacio Lula da Silva, to the rescue, naming him her chief of staff.

But the move blew up in her face when a judge released a wire-tapped phone call suggesting that the appointment -- which would have given Lula ministerial immunity -- was really aimed at saving the ex-president from arrest on pending money-laundering charges linked to Brazil's ongoing Petrobras scandal.

The episode caused a new wave of ant-Rousseff protests and has driven the country's executive and judiciary branches into a standoff.