Presidents are often defined by their first crisis, and Mexico’s new leader is facing a big one: a clash of democratic institutions that could fundamentally upend the country.

On one side is the judiciary. It has come out in full force against the governing party’s complete overhaul of the courts. Federal judges and some Supreme Court justices argue that the changes violate the Constitution and could endanger the country’s democracy.

On the other side is the governing party, Morena. Its congressional leaders have vowed to charge ahead with their plans despite hundreds of legal challenges from the courts. They say the changes are needed to curb judicial corruption.

Next week may present a major test for the president: The Supreme Court will rule on whether to strike down key parts of the overhaul, setting up a direct confrontation between two pillars of government that, legal scholars say, has little to no precedent in recent Mexican history.

How President Claudia Sheinbaum navigates this moment will offer a window into how she wields her power — and what her vision for the country really is. These are questions that have lingered in the minds of many Mexicans since Morena swept the June elections.

Will the president, a scientist by training and a leftist to the core, pursue the aims of her party without giving an inch? Or will she show some flexibility?