MEXICO CITY — In barely three weeks in office, President Andrés Manuel López Obrador of Mexico has been on a relentless gallop to upset the status quo.

He has championed a new law to cut the highest government salaries and raise the lowest ones, and proposed the expansion of social programs benefiting the poor and marginalized, whom he has declared to be his primary concern.

He has aggressively moved forward on a plan to cancel construction of an expensive, partially completed airport.

And in a move replete with symbolism, on the day of his inauguration, he turned the official presidential residence into a cultural center and opened it to the public — producing images of ordinary people, once sealed off from the site by a fierce perimeter of security, freely wandering its grounds in amazement and joy.