This past summer, Washington, D.C.–based Patton Boggs litigation partners Benjamin Chew and Andrew Friedman were a long way from home when they successfully defended the founders of telecom company Dardafone against fraud charges. The nine-week trial, which ended in July with acquittals for their clients, brothers Blerim and Shkelqim Devolli, was in Kosovo, in the Basic Court of Pristina.

As it happened, Chew and Friedman weren’t facing local prosecutors. The indictment was brought by EULEX—a far-reaching European Union program to help reestablish the rule of law in Kosovo after a brutal and ethnically charged civil war in the late 1990s left the southeastern European country in tatters. Operating in Kosovo since 2009, EULEX has taken on an increasingly ambitious caseload, targeting corruption and high-profile criminal matters—even as debate continues over whether its mandate should be renewed after it expires this June.

The EU had previously sent four other civilian and military missions to the Balkans region—ALTHEA, launched in Bosnia and Herzegovina in 2004, is still ongoing—but EULEX is the largest such mission ever deployed by the EU. It has an annual budget exceeding €110 million ($147 million)—paid for by the 28 EU member states and five additional contributing countries, including the United States and Canada—and some 2,250 staff, composed of judges, prosecutors, police and prison officers, and customs officials. EULEX’s executive division investigates, prosecutes and adjudicates complex and sensitive cases; its strengthening division monitors, mentors and advises local police, justice and customs officials.

“In most post-conflict regions, there is an urgent need, immediately after cessation of hostilities, for international assistance on rule of law,” says Jonathan Ratel, a Canadian lawyer who heads EULEX’s special prosecution group of 30 local and international prosecutors. “That’s where we fit in.” His team focuses on the most serious and complex cases involving issues such as organized crime, war crimes, corruption and financial crime. Ratel recently led EULEX’s prosecution in the high-profile Medicus organ-trafficking case, where medical professionals at a Kosovo clinic were charged with illegally harvesting kidneys from individuals brought into the country under duress from various former Soviet states. The case was heard by a panel of three judges—two from EULEX—and achieved five convictions last May.

A EULEX spokesman says the mission has “hundreds” of ongoing investigations, and has over the past five years resolved around 38,000 conflict-related property claims, and successfully prosecuted more than 430 criminal and civil cases.

Patton Boggs’s clients, the Devolli brothers, established Dardafone in 2008 in consortium with New York telecom company Unitel World Inc. Dardafone subsequently entered into a revenue-sharing agreement with Kosovo’s government-owned telecommunications operator, Post and Telecom of Kosovo (PTK), that would allow it to use PTK’s infrastructure. EULEX’s indictment claimed the Devollis, who bought Unitel’s Dardafone stake following a civil dispute, and their business manager had defrauded Unitel and misled PTK. It also alleged that the Devollis had effectively operated an organized-crime enterprise.

The case came to Patton Boggs—which, unsurprisingly, doesn’t have a Kosovo office—via the firm’s of counsel Graham Wisner, who met the Devollis during a business development trip to the country in 2011. In a preliminary hearing, Friedman and Chew, who had to take the Kosovo bar exam to appear in court, secured dismissal of two charges, including that of alleged organized crime. The Devollis were acquitted of the remaining counts at trial, along with their business manager and two government officials who had separately been charged with misusing their authority and exposing PTK to substantial economic damage.

EULEX’s mandate was extended in September 2012 and now runs until June 2014. At press time, Brussels and the Kosovo government were discussing whether and how to extend that term. Serbian prime minister Ivica Dacic said in a recent press conference that he wanted EULEX—which he described as “guarantors of peace agreements”—to remain active “as long as possible.” The ultimate aim, Ratel says, is for EULEX to progressively hand over its responsibilities to local authorities.