Felipe Calderon, who became Mexico's president after the closest election in the country's history, promised to govern with a firm hand.
He soon made good on that promise, deploying troops to take on Mexico's powerful drug cartels shortly after taking office in December 2006 for a single six-year term.
Mr Calderon's decision to pursue the traffickers seems set to be the defining element of his presidency.
More than 30,000 people have died in drug-related violence since 2006: a sign for some the gangs are being squeezed, while others see the rising murder rate in parts of Mexico as an indication of the traffickers' power.
Mr Calderon, candidate of the conservative National Action Party (PAN), won the July 2006 election with a razor-thin lead over his leftist rival, Andres Manuel Lopez Obrador, who challenged the result with mass street protests.
The Federal Electoral Tribunal confirmed Mr Calderon's win after weeks of political and legal wrangling.
President Calderon's first steps to crack down on the drugs gangs saw thousands of troops sent to his home state of Michoacan. Some 50,000 troops have since been deployed to key areas.
He also moved to reorganised Mexico's various police forces.
Drugs and guns
While Mr Calderon's promise to adopt an iron-fist approach to crime may have resonated with voters during the campaign, it has clearly been a high-risk strategy.
The continuing bloodshed - 2010 was the most violent year yet - threatened to undermine public support for the crackdown.
Speaking to the BBC in October 2010, Mr Calderon said he would continue his war on the country's drug cartels until the country was safe.
One of President Calderon's refrains has been that the illegitimate economy - namely drug-trafficking - is driven by demand from north of the border.
He has also repeatedly called on Washington to do more to tackle the flow of guns south.
The issue of illegal migration, and the treatment of Mexicans on the border, is a source of abiding tension between the US and Mexico.
President Calderon has argued for immigration reform in the US, where there are an estimated 12 million illegal immigrants, many from Mexico.
Mr Calderon's term in office also coincided with the global economic downturn. Given its close trading relationship with its northern neighbour, Mexico is exposed to US weaknesses.
But the Mexican economy has proved resilient, with manufacturing performing well, especially the car industry.
Another key issue during Mr Calderon's term has been the condition of the state oil company Pemex. In 2008, President Calderon saw a series of energy reforms passed by Congress, including controversial plans to allow private investment in Pemex.
But the reforms were watered down after months of opposition to any changes to Pemex, which has been in state hands since 1938.
A Harvard-educated lawyer, Mr Calderon is a career politician.
He served as head of the national development bank, Banobras, under his predecessor, Vicente Fox and was energy secretary from 2002 to 2004.
He is also a former president of the PAN, the party his father, Luis Calderon Vega, helped to create.
He is married to Margarita Zavala, who was a PAN deputy in the lower house. They have three children.