The new elected president of Mexico near the qualified majority in Congress

This is the first time that a Mexican leader has been controlling Congress since 1997, before the country completes its transition to democracy.

The size of the majority means Mr López Obrador, Some analysts fear to be able to govern as a populist, only needs the support of a few small parties to carry out constitutional revisions. With this support, the country's two major traditional parties, the Institutional Revolutionary Party and the Conservative National Action Party, will not have enough lawmakers to block the changes.

Constitutional changes are needed to repeal most major economic reforms president's administration

Enrique Peña Nieto,

whose mandate will end on December 1st.

The Peña Nieto administration led the historical opening of the oil industry to private investors and reformed the country's public education system based on the teacher exams and professional merit. During the campaign, Mr López Obrador pledged to repeal the changes in the education sector and to re-evaluate, but not necessarily reverse, the energy reform.

million. López Obrador did not say that he was going to repeal the oil reform. to be Minister of Energy,

Rocio Nahle,

has publicly stated that legislation will be introduced to raise requirements for domestic content, such as equipment and supplies, in petroleum contracts awarded to 80% private companies. Similar legislation in Brazil has resulted in cost overruns, delays and corruption.

Constitutional change is a tool that has been widely used in Latin America by leftist populists to shape the country into its agenda, including concentrating power. The former leaders of Venezuela, Ecuador and Bolivia have all made constitutional rewritings to keep them in power longer.

Some critics of Mr López Obrador fear to change the long-standing ban on presidential reelection. But the president-elect has never hinted that he wanted to stay in power beyond his elected term, and during his victory speech, he swore to his supporters never to become a dictator.

Mexican assets and the local currency rallied signaling that broad Congressional support by Mr. López Obrador is not yet a source of concern for investors.

López Obrador said that he wanted to change the constitution to eliminate immunity from prosecution against the president and all officials, including lawmakers. He also said that he wants a constitutional change to include the possibility of revoking the president's term if this is decided by the Mexican people. He said the first of these referendums will be in the mid-term elections of 2021.

"The big question now is whether the electoral coalition of Mr. López Obrador will become a successful legislative coalition," he said.

José Woldenberg,

a political analyst and former head of the electoral agency. "If that happened, it would be easy for him to pass a law to reach agreements with different parties, depending on the problem."

López Obrador repeatedly stated that sending laws to Congress would not be a priority, focusing instead on the deeply rooted fight against corruption and on the restructuring of Mexico's budget to save money and increase public investment. But he made those promises during the campaign, while little expected that he would get a majority in Congress let alone get a two-thirds majority, analysts said.

Spokesman López Obrador said that despite the legislative majority, the plan remains to send some bills to Congress. The "major" changes to the constitution should be submitted to Congress, beyond the two proposals on immunity and revocation of mandate.

López Obrador's coalition would just need the support of the Center-left Citizens Movement to obtain a qualified majority in the lower house. In the Senate, he would need the combined support of the Citizens Movement, the left-wing party of the democratic revolution – his former party – and the Green Party.

After Sunday's election, the party of Mr. López Obrador, known as the Spanish acronym Morena, will also have a majority of state legislatures-something had to amend the constitution. Morena will control 22 of the 32 state assemblies, according to preliminary results.

Morena officials say party legislators will be free to vote with their conscience and that López Obrador will be respectful of party representatives. And they say that the three parties supporting Mr. López Obrador are different organizations that will vote in Congress according to their principles.

"We will not give a blank check to López Obrador"

Tatiana Clouthier,

The campaign director of Mr López Obrador. Ms. Clouthier has been elected legislator and is one of the principal political advisers of the president-elect

. But the victory of Mr. López Obrador was so overwhelming that a likely scenario is that the parties supporting Mr. López Obrador will remain united, while small opposition parties will be encouraged to cooperate with an administration of López Obrador , said Mr. Woldenberg

. Write to Juan Montes at [email protected]