President Macri's Man in Washington

WASHINGTON -- U.S. President Barack Obama and recently elected Argentine President Mauricio Macri have a historic meeting today in Buenos Aires, holding the first bilateral summit between their countries in almost two decades.

Meanwhile, about 5,200 miles away from the photo ops, the Argentine in charge of stewarding the budding relationship is just settling into his new home in Washington, D.C.

That man is 45-year-old Ambassador Martín Lousteau, appointed by center-right Macri in December. The diplomat and former politician has big tasks at hand, among them improving a relationship that deteriorated under Argentina's former President Cristina Fernández de Kirchner and persuading U.S. investors that Argentina is once again open for business.

Lousteau's appointment, which surprised some, might also say something about Macri's priorities and his ways of governing.

"There have been many names that had been talked about for this ambassadorship but his wasn't one of them," Mark Jones, a fellow in political science at Rice University's Baker Institute, says of Lousteau. "But he is somebody who has the CV -- the academic and intellectual capacity to do an excellent job as ambassador to the U.S."

Compared to Cecilia Nahón, Argentina's previous ambassador to the U.S., Lousteau has a "broader international perspective," Jones says.

Lousteau earned a master's in economics from the London School of Economics and Political Science. He's written four books, been a columnist for one of Argentina's largest newspapers, served as a member of parliament and advised the head of the Central Bank of Argentina, among other government posts. He also started his own economic and political consultancy firm and in 2012 was selected as a World Fellow at Yale University.

He spent two months in Washington in 1989, when his father taught at George Washington University. The city has now changed for the better, says Lousteau, who arrived about a month ago with his young son and wife, Argentine actress Carla Peterson.

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Like many as his fellow Argentines, Lousteau once put faith in the Kirchner government and later turned against it. At 37, he served in Fernández de Kirchner's government as minister of economy and production. He lasted less than five months, resigning due to disagreement with the government's approach to rising inflation and the fallout from a three-week farmer strike over a tax hike he devised on soy exports.

"More than anything else, that helped launch him as someone who was seen as an anti- Kirchner," says Jones. "It's pretty universally excused as the innocence of youth ... He was intelligent and very well-meaning but simply didn't fathom what he was getting himself mixed up in. Then to his credit, he immediately left."

After Lousteau left the Kirchner government he eventually entered electoral politics, starting his own political party called ECO. Last July, he ran for head of the Buenos Aires city government, where he was defeated by Horacio Rodríguez Larreta, a member of Macri's PRO party.

By tapping Lousteau -- a member of PRO's opposition -- for the ambassador post, Macri appeared to be sending a message. That was reinforced when Macri brought his election opponent, Sergio Massa, with him to the World Economic Forum in January.

"Macri has been trying to signal to the opposition -- to the Peronists -- that he is willing to work with them. He doesn't want to contribute the political polarization in the country," says Harold Trinkunas, senior fellow and director of the Latin America Initiative at the Brookings Institution. "The fact that he would take someone who had worked with Kirchner, who had competed against his political party in the past, and now name him to one of the most important diplomatic appointments, I think it's is a signal."

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As for his priorities, Lousteau said in an interview that he sees room for increased engagement and collaboration in investment, the energy sector, education, national security and climate change. He believes the U.S. and Argentina have much more in common than many assume, and hopes the countries can once again engage not only at a government level, but also in business and civil society.

Lousteau says Argentina has a perception problem in the U.S., in part due to the prolonged focus on Argentina's holdout creditors. The issue may soon be resolved, ending Argentina's 15-year isolation in the global credit markets sparked by its 2001 default on about $100 billion in debt.

"When I finish my time here, I would like a wider audience that understands what Argentina is. What the possibilities are," he says. "Because once that is unlocked then all of the potential is unlocked."

That's a lot of diplomatic talk. But if it's followed by action in Buenos Aires, the U.S. and Argentina may indeed be able to start a new chapter. As for today's agenda, the two leaders planned to announce new joint efforts on energy, climate change, and combating drugs and crime.

"Argentina has been so isolated diplomatically in Washington under the Kirchner government," Trinkunas says. "The focus is really rebuilding the breadth of the relationship, which was at one point strikingly wide. Argentina was our closest partner in Latin America during the 1990s."

With Obama in Argentina now and Macri coming to the U.S. for a nuclear safety summit just a few days later, Lousteau doesn't have much time to get his bearings.

"There are a whole bunch of presidents going back and forth," Trinkunas says. He'll need to bring the relationship back, and "do so relatively quickly."

Devon Haynie is news editor, international for U.S. News. You can follow her on Twitter or email her at dhaynie@usnews.com.