MEXICO CITY (AP) — The former mayor of Mexico City will be the dominant ruling party’s presidential candidate, moving the country closer to electing its first ever female president next year.

The decision driven by polls of Morena party members means that Claudia Sheinbaum will run as the party’s candidate in the June presidential election. Mexico’s constitution bars outgoing President Andrés Manuel López Obrador from a second six-year term.

Morena national council president, Alfonso Durazo said that Sheinbaum beat former Foreign Affairs Secretary Marcelo Ebrard, by double figures in five party surveys.

Sheinbaum is a close ally of the popular López Obrador and as Morena’s candidate she will enjoy a distinct advantage in June.

“I'm excited,” Sheinbaum said, thanking each of her competitors by name with the exception of Ebrard who was not present. “I feel very proud, very honored” to have been part of this movement since its inception.

Last week, a broad opposition coalition selected female lawmaker Xóchitl Gálvez as its candidate.

Sheinbaum, 61, led Ebrard in recent polling and both had stepped down from their positions to campaign full time.

Durazo said “the result of this exercise is definitive,” adding that even though there were difficulties they didn’t affect the final result. He called on party members to close ranks behind Sheinbaum’s candidacy.

The other party candidates present at the announcement commended Sheinbaum. Ebrard was the only candidate who did not attend.

Hours before the announcement Wednesday, Ebrard complained of irregularities in the process, said it should be done over and accused his party of increasingly resembling the Institutional Revolutionary Party that ruled Mexico for 71 years, famously allowing each president to select his successor. He said he would decide Monday how to proceed.

Other party leaders seemed to respond indirectly to Ebrard's criticisms, saying the internal party process was transparent and democratic.

Trained as an environmental scientist, Sheinbaum sits solidly on the left of the ideological spectrum. She frequently echoed López Obrador’s rants against the neoliberal economic policies of earlier Mexican presidents, blaming them for the country’s gaping inequality and high levels of violence.

López Obrador had said that he would let the party faithful decide its candidate.