BOGOTA — All signs indicate an imminent victory for the opposition in Venezuela's legislative elections Sunday, and that means the beginning of the end for the authoritarian regime of President Nicolás Maduro, and for 16 years of socialist Bolivarian rule launched by the late Hugo Chavez.

And yet, the government's blatant superiority in strength, political violence, disqualification of opponents and the possibility of fraud are setting off alarms, notably at the Organization of American States (OAS).

As pessimism builds at the presidential palace in Caracas, the Venezuelan leadership has adopted a more aggressive discourse, using abusive language and, worse, implicitly threatening that it won't recognize the results of Sunday's polls. Maduro has said that "in that hypothetical, distorted, rejected" situation (meaning an opposition victory), he would assume his "political and military" responsibility and even "take to the streets."

The explanation for such crazy talk is in what the polls are saying, that the opposition is between 20 and 30 points ahead of the pro-government coalition. Amid the simmering distrust and tensions, an opposition politician was shot dead days ago at a rally. Luis Manuel Díaz, a regional leader for the opposition MUD coalition, was killed at a gathering that included Lilian Tintori, wife of detained politician Leopoldo López who has herself become one of the opposition's most visible international faces.

The OAS, changing its previous, muted conduct, vigorously condemned the incident, and its secretary general, Luis Almagro, issued a communiqué urging the Venezuelan government to investigate. It deplored the intimidation of opponents and declared that the elections can't be an "exercise in brute force, violence and fear."

In typical form, President Maduro called the OAS "trash." Almagro wrote back saying he would be trash if he "were lenient with killings, threats and the logic of fear. We would be trash if deaths in Venezuela did not affect us." He urged Maduro to disband armed groups, "especially those dependent on the government and its party," the socialist PSUV.

Maduro in Barcelona, Anzoategui State, Venezuela, on Nov. 18 — Photo: Venezuela's Presidency/Xinhua/ZUMA

Almagro is right, of course, and all regional governments should state their support for the OAS posture, especially since the other regional grouping, UNASUR, and its secretary general, Ernesto Samper, a former president of Colombia, have had a shameful attitude towards Venezuela so far.

Several issues are at stake on Dec 6. One is the need to wrench control of parliament from the government and its allies. The president has so far had tight control of not only the three branches of government — executive, legislative and judiciary — but also other departments. The opposition Democratic Unity Roundtable (MUD) is threatening this accumulation of power.

Venezuelans will be voting for 167 legislators, with 84 constituting a simple majority. We should recall that in 2010, the opposition won 65 seats, though the mathematical logic will not apply here, as this parliament's meddling with electoral boundaries — gerrymandering, as Americans call it — will make it difficult for the opposition to win the 100- or 110-seat absolute majority it needs to make big changes in the country. This means that the opposition, which is stronger in cities, will need to win about 60% of all votes just to get a simple majority. Go figure.

Either way, this Sunday could deliver the Bolivarian movement its first big electoral defeat since the constitutional referendum of 2007. With serious problems of corruption, shortages, inflation, crime and an increasingly authoritarian government, Venezuela needs changes now and in the medium term. Voters have the decisive word on this, and the government must heed their verdict.