First, the big news:

MEXICO CITY — The party that ruled Mexico for decades with an autocratic grip appears to have vaulted back into power after 12 years in opposition, as voters troubled by a bloody drug war and economic malaise gave its presidential candidate, Enrique Peña Nieto, a comfortable victory on Sunday, according to preliminary returns and exit polls.

The victory was a stunning reversal of fortune for the centrist Institutional Revolutionary Party, known as the PRI, which was thought to be crippled after its defeat in the 2000 presidential election ushered in an era of real multiparty democracy here.

The autocratic suits of the PRI are back in the saddle again—in part because the Mexican political structure is tired of chaotic drug-war mayhem and wants to give the stability of old-fashioned, genteel corruption another try.

If the past is prologue, that is good news for the Sinaloa cartel (the gentleman farmers among Mexico's drug gangs) and other big businesses. And that is bad news for the Zetas (the latest, fiercest new player among Mexico's larger drug gangs), political dissidents, and other upstarts. And it might mean that the drug war will have a brief surge in violence—as the PRI and the Sinaloa collude to exterminate their rivals—but will ultimately cool down for awhile*.

Let's start with a little historical background on the Sinaloa and the PRI from this 2010 Stranger article:

Major Mexican landowners had been growing marijuana and opium poppies and selling them to the U.S. long before the Harrison Narcotics Act of 1914 (the first major federal drug prohibition—prior to that, even the Sears, Roebuck catalogue advertised a syringe and a dose of cocaine for $1.50). Those Mexican landowners were aligned with, or outright members of, the Mexican political establishment...

Eventually, over the course of years in the drug trade [after US prohibition in 1914], the major landowners and marijuana and poppy growers of northern Mexico mutated into the so-called Sinaloa cartel. Their longtime political-establishment allies became the Partido Revolucionario Institucional (PRI), which held power in Mexico for over 70 years. Their relationship, relative to today's narco-chaos, was mostly stable and calm. It is not entirely accidental that the PRI lost its political hegemony at roughly the same time (the late '90s) that the Sinaloa lost its narco-hegemony—nor is it accidental that "higher levels of violence connected with drug trafficking in the 1990s were observed mostly in those states where the political opposition [to the PRI] had gained power," as historian Luis Astorga notes.

The PRI also has a long history of quashing political dissent and getting too cozy with banks and TV stations. From this morning's Guardian:

The candidate [Nieto] has also faced protests by students who shook up the electoral campaign with a movement that rejected his candidacy as a step back in the country's fledgling democracy, and focused attention on alleged bias in his favour by the media.

I don't doubt the allegations of media bias. And check out this story from June 19 on the Narco News blog:

A civil lawsuit filed this month in US court against several Mexican companies and three top officials from the campaign of Mexican presidential candidate Enrique Peña Nieto alleges the parties engaged in a conspiracy to convert campaign funds derived from narco-traffickers to their own personal use by employing a scheme to defraud a US company.

The lawsuit also alleges that Peña Nieto campaign operatives threatened a plaintiff that the money “was funded from companies owned by drug cartels and it was further stated that Jose Aquino [owner of Frontera Television Network] must be very careful not to make any noise or his life is in danger.”

Why this is bad news for the Zetas, the terrifying upstarts in Mexico's drug war, and leftist political dissidents: The Zetas are renegades, and the PRI does not like renegades. They like good old boys like the Sinaloa.

The Zetas were trained by the U.S. School of the Americas as a special-forces unit to fight drug cartels, then hired by the Mexican government, then hired away to the cartels to be their special-forces units. (The cartels pay better.) The Zetas eventually realized they were the baddest asses in the game, so split off to form their own DTO (drug-trafficking organization) and have been waging a vicious battle royale ever since, further destabilizing the drug trade. (The Zetas are also credited with introducing narco-terrorism—killing more innocent civilians and posting executions on YouTube to terrify the general populace, instead of confining their murders to simple business moves.)

And the Zetas have been stepping up their game against the Sinaloa lately, trying to push the old graybeard of the drug trade off his rocking-chair throne. The Zetas are the Goneril—the sadistic, bloody, ungrateful child—to the Sinaloa's King Lear.

But the PRI is back in power now, and the PRI historically favors its old gentleman-farmer friends in the Sinaloa cartel. And the Sinaloa surely helped the PRI's election bid. (Is it a coincidence that, in the days leading up to the election, Blog del Narco noticed lots of executions and riots in Sinaloa territory? I don't think so. I think the Sinaloa are cleaning house and reasserting themselves.)

I also suspect Mexican power-players are taking a page from the Japanese Yakuza handbook—one big gang with a monopoly on crime means less warfare, less chaos, calm institutionalized corruption, and fewer terrifying civilian deaths. The downside is less democracy. It's not a sustainable strategy in the long term but, at this point, Mexicans may be willing to settle. And while the Zetas have leveraged mayhem to their short-term advantage in the past, they may have screwed themselves with their narco-terrorism strategy by making the Mexican power establishment yearn for the old days. At least then you knew who might kill you if you crossed him. These days, the bullet/machete/chainsaw could come from any direction.

My prediction: Expect a lot of dead Zetas in the coming year and then a general cool-down as the oldest Mexican drug cartel and the most institutional political power in Mexico reestablish their hegemony.

*Of course, this is wild extrapolation and I could be 100% wrong. This kind of stuff is impossible to predict.