MEXICO CITY — In a country where there were 2,452 homicides in January alone, there are few options for a president who campaigned as a pacifist. Just ask Andres Manuel Lopez Obrador.

The man who told voters last year that Mexico's violence could be stopped through reconciliation — "hugs, not gunshots" was one of his slogans — will dispatch the military and federal police across the country to fight criminal groups. That force will get a new name: the national guard.

Mexico's National Congress approved the plan Thursday, laying the groundwork for Lopez Obrador's most significant security policy to date. Although it has overwhelming political support, critics say the approach marks an about-face for Lopez Obrador and a return to the failed militarization strategy of previous administrations.

It was clear that Lopez Obrador, known by his initials AMLO, had to do something. In 2018, there were 28,816 homicides, a 15 percent increase from the previous year. The most recent figures added up to the bloodiest January since Mexico began keeping such records in 1997. Drug cartels, gangs of fuel thieves and other organized-crime groups exert enormous influence across most of the country.

"With the creation of the national guard, we think this is the way we're going to guarantee the peace and tranquility of the country," Lopez Obrador said.

The new force will largely be used to fulfill traditional police responsibilities, officials said, and it will have a five-year limit. It initially will consist of 50,000 soldiers, federal police officers and marines.

Once the majority of state legislatures approve the national guard - a near certainty given that Lopez Obrador's party controls many of them — it is expected begin operations in mid-March.

But it remains unclear exactly what the force will do: Will it detain low-level criminals or focus instead on a concerted fight against drug cartels? In theory, it is charged with doing both. Lopez Obrador likened the force to U.N. peacekeepers, an analogy that confused many here, given that Mexico's security problems are a far cry from the civil wars typically mediated by the United Nations.

Beginning in 2009, then-President Felipe Calderon tried the latter strategy, which prompted a wave of violence as cartels fractured and fought one another for territory. In recent years, the military also has been accused of human rights abuses, including killing 22 people in a warehouse in the town of Tlatlaya in 2014. Seven soldiers were charged in the massacre, but only one served a jail sentence.

"What worries me most is that we're basically accepting that Mexico will be a country policed by the military for the foreseeable future," said Esteban Illades, the editor of Nexos magazine. "After 12 years of fighting cartels, this government that once promised a different approach still hasn't found a sensible solution. They're just repeating what they've been doing."

The national guard is also an attempt to fix another major problem that has exacerbated Mexico's security challenges: Many consider local police agencies to be among the country's most corrupt and dysfunctional institutions. In some cities, including Acapulco, officials deemed the local police so corrupt that they disarmed the entire force.

The national guard will report to a civilian leader, but much of its leadership will remain in the military. Where local police often have maintained quiet connections to local criminal groups, the hope is that the national force will be a more effective and more honest enforcement arm, managing a range of enforcement from highway checkpoints to high-level investigations of drug trafficking. The federal police are generally considered more reliable.

For years, the military's deployment in domestic affairs has been hotly debated in Mexico. Lopez Obrador's immediate predecessor, Enrique Pena Nieto, introduced a policy that allowed troops to take on police duties. But the Supreme Court of Justice ruled last year that the policy was unconstitutional, arguing that the military could not be deployed indefinitely. Part of Lopez Obrador's push for the national guard called for Congress to change the constitution, which it did, to allow for the creation of the new force.

Human rights groups have expressed concern. In a statement in January, Amnesty International said it worried that the national guard "would be involved in an indeterminate number of cases without first being adequately assessed."

In a statement, Mexico's National Commission of Human Rights (CNDH) also expressed skepticism, saying the new force would "create the risk of human rights being violated and would not in any way guarantee or contribute in a substantive way to ending impunity."

Mexico's Congress attempted to address some of those concerns in its legislation. For example, members of the national guard who are accused of committing crimes would be prosecuted in civilian courts, not military ones. Also, Mexico's 31 states would have significant control over the local actions of the force.

In an interview, Ruben Perez Sanchez, the commission's director of legal affairs, said the changes to the national guard legislation alleviated some of the commission's concern, but he added: "Our concerns about the human rights abuses of the armed forces are permanent."

Even senators who initially raised concerns about the increasing militarization, such as Patricia Mercado, ended up approving the force in what was a unanimous vote in the upper house.

In an interview, the at-large senator said she decided to vote in favor partly because the legislation also allows the "improvement and reform of state and local police even as the national guard is being created."

But she cautioned against any suggestion that the new force will solve Mexico's problems.

"I hope the government doesn't create the expectation that this is going to be a panacea," she said. "There is still a major problem with impunity. The justice system needs a profound change."

The Washington Post's Gabriela Martinez contributed to this report.