Mauricio Macri, a conservative, is Argentina's new president. His victory in a ballot earlier this month ends 12 years of rule by the Peronist Justicialist Party and heralds fundamental shifts in the country's economic and foreign policies. While change is needed, it will be difficult; the Peronists still control the legislature and the hole that has been dug means reform will cause real pain if it is to be effective.

Macri won just over 51 percent of the votes in a runoff election against former Vice President Daniel Scioli. Scioli prevailed in the first-round vote but did not have a sufficient majority to prevent a runoff. While turnout in the runoff was 82 percent — high enough to claim a mandate — the margin of victory is still slim enough to empower the opposition to resist Macri's agenda.

That agenda is pro-business. He comes from a family of business professionals — his father, one of Argentina's richest men, made his money in construction — and Macri was the head of Boca Juniors, one of Argentina's most popular soccer teams. Success there propelled him into politics: He served two terms (eight years) as mayor of Buenos Aires, which served as his gateway to national politics.