Behind a white door on a graffitied backstreet in Sarajevo, a company with no meaningful infrastructure history is believed to be on the verge of securing contracts worth more than one billion dollars. AAFS Infrastructure and Energy is understood to be close to finalising a concession that would see a gas pipeline built across the Balkans, designed to carry liquefied natural gas shipped from the United States as a replacement for Russian supplies that have long underpinned the region's energy supply. Senior Bosnian officials, who requested anonymity given the sensitivity of the negotiations, have described the project as potentially the most consequential infrastructure undertaking in the country's modern history. What the company appears to lack in relevant experience, it may compensate for through political proximity. Two of AAFS's representatives are reported to have significant personal ties to Donald Trump: one is a Washington attorney who has represented members of the Trump family in political litigation, while the other is the brother of a former national security adviser. Both figures are said to have participated in efforts to challenge the outcome of the 2020 presidential election, a cause that has remained central to Trump's political identity. A Guardian investigation, drawing on leaked documents, corporate filings, and interviews with current and former officials on both sides of the Atlantic, has sought to examine how the company came to occupy such a strategically prominent position. The findings are seen by analysts as illustrative of a broader pattern under the current administration, in which the boundaries between foreign policy and private enrichment are increasingly difficult to discern. The stakes in the western Balkans extend well beyond commercial gain.…