WASHINGTON – US President Barack Obama sought to capitalize on Mauricio Macri’s election to open a new, less contentious chapter in relations with Argentina, vowing to improve trade ties Wednesday. Holding out the prospect that Argentina’s battered economy could get some much-needed help, Obama called Macri to offer the pro-market president elect his congratulations. Obama “conveyed his commitment to deepen cooperation on multilateral issues, improve commercial ties and expand opportunities in the energy sector,” according to the White House. After a decade in which Argentina was viewed as a financial pariah, that is a significant change in tone. The country’s multiple defaults have left it enmeshed in a net of law suits cast by creditors, many of whom are US finance houses. Those legal disputes are unlikely to disappear, but without the economic populism of Cristina Kirchner and her predecessor and late husband Nestor Kirchner, Western governments may be more willing to engage. In a sign of how Argentina’s clout has been dampened, Obama has not yet traveled to Latin America’s third-largest economy during his seven years as president.