MEXICO CITY — As the Nobel Peace Prize was being awarded in Oslo last week, a young man dashed on stage, unfurled a Mexican flag streaked with red paint and begged for help for his country because more than 40 college students have been missing for months after clashing with police.

At the Latin Grammy Awards ceremony in Las Vegas last month, the big winners, Calle 13, shouted solidarity with the victims as they performed.

At home, mass marches have regularly filled streets with angry calls for the government to act against corruption and crime.

But is the country’s political class listening?

In the coming days, Mexico is expected to name a special prosecutor to investigate corruption — a supposed Eliot Ness who’d spare no sacred cows and answer the clamor of the public.

The prosecutor is supposed to finally root out bribery, favoritism, kickbacks and reveal the kinds of organized crime that prosecutors say were at play in the case of the missing students.

That kind of prosecutorial determination may be what the public demands. But what it’s getting is a prosecutor with little of the independence necessary to carry out the stated mission, government watchdog groups say.

The new position will operate under the attorney general’s office — headed by an ally of President Enrique Peña Nieto, who will have veto power over the Senate’s nominee.

But the president himself is facing accusations of conflict of interest over a house his wife tried to buy from a government contractor, raising public concern about how aggressive a special prosecutor can be.

So in a time of widespread tumult over the missing students, presumed dead at the hands of authorities working with drug gangs, Mexico faces an ever-widening breach between the political class and the demands for change.

The parties, all weakened or lacking moral authority on corruption and the rule of law because of their own misdeeds or lack of action, are seen as failing to channel the passion of the streets.

Peña Nieto’s governing Institutional Revolutionary Party has a legacy of corrupt rule, and polls show a lack of faith in him and in how he has handled the crises. The left-leaning Party of the Democratic Revolution is in power in the violent state and city where the students disappeared. And the conservative-leaning National Action Party, buffeted by internal discord, still gets tarred for failing to control the drug violence that soared when it held the presidency before Peña Nieto.

“What has been proposed as solutions are like treating cancer with an aspirin,” said Juan Pardinas, a political analyst at the Mexican Institute for Competitiveness, a research group based here. “There is a kind of deafness on their part without recognizing the huge opportunity to change things in Mexico as a result of this crisis.”

New polls have shown Peña Nieto with the lowest popularity ratings of his two years in office, as well as falling confidence in public institutions and in the political process in general, in which under-the-table money, illicit and not, flows freely despite tight controls on campaign spending.

Dragging down the public mood are a series of cases questioning the integrity of the state.

First came the abduction of the 43 teacher-trainee students in rural southern Mexico at the hands of the police and, according to the authorities, a local mayor working with a drug gang.

Then a local news site published details of a luxurious house that Angelica Rivera, the mayor’s wife, was buying on credit from a contractor that had done a lot of government business.

The owner of the company that built the house was part of a Chinese-led consortium that had just won a government contract to build a high-speed train, though the bid was later canceled.