Question: The failed Escobar Rebellion of 1929 challenged the political power of what political leader, who had been the interior minister under Mexican President Alvaro Obregon?  
Sentence (from "Plutarco Elías Calles"): The 1924 Calles presidential campaign was the first populist presidential campaign in the nation's history, as he called for land redistribution and promised equal justice, more education, additional labor rights, and democratic governance.
Relevant evidence: No