The European Union and the Mercosur bloc of South American countries formally signed a long-sought landmark free trade agreement on Saturday, capping over a quarter-century of torturous negotiations to strengthen commercial ties in the face of rising protectionism and trade tensions around the world. The signing ceremony in Paraguay's humid capital of Asuncion marks a major geopolitical victory for the EU in an age of American tariffs and surging Chinese exports, expanding the bloc's foothold in a resource-rich region increasingly contested by Washington and Beijing. It also sends a message that South America cultivates diverse trade and diplomatic relations even as US President Donald Trump declares dominance in the Western Hemisphere.