Since taking office nearly two years ago, President Enrique Pena Nieto has sought to project an image of Mexico on the move, beating back chronic drug violence and pressing ahead with historic constitutional and economic reforms, even offering to contribute soldiers to UN peacekeeping missions in other parts of the globe.

The problem is that, back home, Mexico's grotesque cycle of violence continues, with soldiers and police implicated in recent atrocities. Pena Nieto's determination to focus on Mexico's moment has been derailed by Mexico's mess.

International human rights groups are calling the massacre of 22 suspected gang members in southern Mexico this year a test case for the president, and the world is demanding answers in the forced disappearance of 43 teachers' college students, who are feared to be buried in mass graves discovered after they vanished Sept. 26.

Pena Nieto addressed the violence this week — twice — as everyone from outraged Mexicans to the United Nations and the U.S. State Department called for a full accounting in both mass killings.

"There's no room for the slightest impunity," Pena Nieto said Thursday, referring to the disappearance of the 43 students of the school in Ayotzinapa. "It's time to reiterate, without a doubt, the need to work fully in coordination with other levels of government ... each assuming its responsibility."

The macabre headlines — many of the bodies were burned, one victim had his skin peeled from his skull, and nearly two dozen local police have been arrested — are not what Pena Nieto was hoping for in a month in which his security forces nabbed two top drug traffickers and the president was awarded the Global Citizen Award by a U.S. think tank.

Human Rights Watch has said the earlier massacre — which the government was slow to investigate after an Associated Press report unearthed evidence of alleged extrajudicial killings by soldiers — is a test case for Pena Nieto on human rights.

"It has become increasingly evident that in the process of not allowing this single issue to hijack this administration, he has made the mistake of ignoring it altogether," said Tony Payan, director of the Mexico Center at Rice University's Baker Institute for Public Policy.

Pena Nieto took office two years ago vowing to change the narrative after his predecessor's bloody war on drugs, portraying Mexico as ready to lead and fertile ground for foreign investment. His administration has pushed through reforms to the education system, changed the tax code and opened the energy sector to more foreign investment, among other achievements. He can also point to a string of high-profile drug arrests including that of Juarez cartel leader Vicente Carrillo Fuentes who was caught on Thursday, and Hector Beltran Leyva, who was apprehended last week while eating fish tacos in a central Mexico seafood restaurant.

But even those successes have come with grim side effects. As the major drug organizations have been broken up, smaller and often more-violent bands have taken their place, causing a spike in non-drug crimes that more directly affect citizens, such as kidnapping and extortion. The students in the southern state of Guerrero allegedly went missing at the hands of corrupt police working with the Guerreros Unidos, which was born out of the breakup of the once-powerful Beltran Leyva cartel.

The mayor of Iguala, where the students disappeared, is on the run amid accusations he and his wife were linked to the drug gang.

"This is a moment for new ideas, not just telling us to all to behave well," Milenio newspaper columnist Carlos Puig wrote Friday of Pena Nieto's response so far. "It's time for something much more serious that just 'coordination.' "