Photo credit to Miguel Schincariol, AFP/File.

On the Friday before Brazil’s first-round general election, the biggest story is that the runoff that everyone expected — a showdown between incumbent president Dilma Rousseff and former environmental minister and presidential candidate Marina Silva — may not actually happen.

It’s a stunning turn of events. Silva, the candidate of the Partido Socialista Brasileiro (PSB, Brazilian Socialist Party), is still the favorite to advance to a runoff against Rousseff, the candidate of the governing Partido dos Trabalhadores (PT, Workers Party), which has led Brazil since the 2002 election of Luiz Inácio Lula da Silva.

But it’s going to be a lot closer than anyone thought for the past six weeks, while Silva benefited from the sympathy of being the candidate to replace her late running mate, former Pernambuco governor Eduardo Campos, who died in a plane crash on August 13.

Can anyone guarantee, 48 hours out from election day, what will happen?

In a word, no.

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RELATED: In Depth — Brazil

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The latest Datafolha poll, taken between October 1 and 2, shows Rousseff, the candidate of the governing  with 40% of the vote to just 24% for Silva, and 21% for Aécio Neves (pictured above with Rouseff). When all undecided voters are allocated or eliminated, Rousseff wins 47% of the vote — just short of a stunning outright victory on Sunday. Rousseff would win a runoff against Silva by a margin of 48% to 41%.

Neves, a senator and the former governor of Minas Gerais, the candidate of the center-right Partido da Social Democracia Brasileira (PSDB, Brazilian Social Democracy Party), could actually pip Silva to the runoff.

It’s not likely, but it’s a much more possible outcome than anyone believed even earlier this week. 

Even in the 2010 election, Silva managed to win 19.33% of the first-round vote as the candidate of Brazil’s Green Party, a party with much less organizational support than the Brazilian Socialist Party. It’s incredulous to believe that she’ll win even less this time around, with an electorate that has emphasized its receptivity to change — from the 2013 protests to the low poll ratings that Rousseff has suffered over the past months.

Silva’s drop in the polls was always inevitable to some degree.

As the sympathy and shock of Campos’s death faded into the background, Rousseff and Neves would be able to attack Silva with greater ease.

Silva’s campaign has, as I’ve argued today in The National Interest, ably portrayed her both as a radical departure from the status quo and as a conservative pair of hands. She’s a historic Obama-like figure, a poor child of Amazon rubber tappers, an environmental activist and the first potential Afro-Brazilian president and without ties to the political elite. She’s also a socially conservative evangelical who’s promised to stop interfering in the currency markets, to introduce greater fiscal discipline and pull toward Washington and away from Caracas.

While that’s allowed Silva to grab for a broad majoritarian coalition, it’s arguably left her more greatly exposed in the first-round vote. Rousseff and the left can argue that the social welfare programs of the last 12 years will be endangered by a Silva administration. Neves and the right can attack Silva for being a flaky activist who, just days ago, posited that the raw material of politics is ‘dreams.’

The obvious regional analog is to Enrique Peñalosa, the business-freindly Green Party candidate in Colombia’s presidential election who, in two months, went from a credible runoff challenger against president Juan Manuel Santos in March to discredited fifth-place finisher in May.

Moreover, both the PSDB and the PT have institutional strength and funding that far outweighs the PSB. In the case of the Rousseff campaign, they also have the support of a half-dozen parties, including the powerful (if amorphous) Partido do Movimento Democrático Brasileiro (PMDB, Brazilian Democratic Movement Party), which holds the vice presidency and more seats than any other party in the Brazilian congress, and has found its way to supporting each of the last three governments, including neoliberal reformer Fernando Henrique Cardoso.

Until recently, the PSB was a minor player in Brazilian politics, a ‘fisiológico,‘ the kind of shape-shifting, nominally center-left amoeba  that exists solely to win a piece of the governance pie. It’s a game that the PSB played well as a supporting extra in the Lula da Silva and Rousseff governments for 12 years — until 2014, when Campos pulled the party out of power. It’s on something of a roll, and it actually controls six governorships, one more than the Workers Party.

But imagine what might happen if Silva survives, however narrowly, to advance to the October 26 runoff.

All of a sudden, she’ll be the sole challenger to Rousseff, a figure that Brazil’s business and investor community has grown to scorn. She’ll pick up the support of Pastor Everaldo, an evangelical who’s running as the candidate of the minor Social Christian Party, and Eduardo Jorge, the Green candidate (and one of the co-founders of the Workers Party).

She’ll also likely win the support of Neves and the PSDB, along with Brazil’s entire business class.

With three weeks until the vote, she’ll also find the dynamics much changed, with enough funding and equal access to television to run a campaign on nearly equal terms as Rousseff.

In the ebb and flow of an election like this, Rousseff may actually be peaking too soon. If Silva survives the onslaught of Rousseff’s campaign and emerges on the morning of October 6 with 20 more days in a head-to-head race, it’s hard not to imagine the race tightening, making it the closest race since Lula da Silva narrowly lost the 1989 election by a margin of 53% to 47% to Fernando Collor (a center-right candidate who was impeached two years after his election).

Even in the 2010 race, when Rousseff easily dispatched the former São Paulo governor and mayor José Serra, who is perhaps the Bob Dole of Brazilian politics, there were a few days early in the runoff campaign where Rousseff’s questionable stand on abortion nearly allowed Serra to catch up to her.

Colombia, again, offers an apposite analogy. On May 25, conservative challenger Óscar Iván Zuluaga beat Santos in the first round by more than 3%. With the government’s peace talks with FARC on the line, Santos regrouped in the runoff and defeated Zuluaga by 6%.

Brazilian voters may come to view a Dilma-Marina race similarly. What now look like weaknesses 48 hours until the first-round vote could well become strengths 48 hours after the vote.