Each president controlled the PRI and decided its candidates for Congress. Thus, he never had to lobby Congress for anything. But now, no party holds a congressional majority. Legislators are interested in establishing their independence and taking on their new role as a check on presidential power. These are normal adjustments.
People are accustomed to seeing the party in power controlling all aspects of Mexican life.
So it's surprising to see all these conflicts that are normal in any democratic system. Most stunning, though, is the trouble Fox has had with his own party. Many PAN leaders have long had doubts about Fox's devotion to their traditional ideology. In 1988, Fox was among a crew of businessmen who joined the party. Their energy and pragmatism changed the PAN into a party with broader appeal.