When Washington suddenly starts writing nice things about some Balkan country, it is worth checking what that country has under its feet and above its ground. This time it is Serbia, and Forbes magazine has counted four reasons why Belgrade has suddenly become important to the Trump administration.

The first reason is gas. Serbia sits on the so-called Vertical Gas Corridor, through which American liquefied gas and Azerbaijani gas are meant to reach Europe. According to the analysis, Belgrade has set aside around 1.6 billion dollars for energy security, which could enable the full nationalisation of the oil company NIS if Russia blocks its sale to Hungary's MOL.

The second reason is lithium. Forbes claims Serbia holds the largest lithium reserves in Europe and that the Jadar project could cover ninety percent of the continent's current needs for this strategic mineral. And here lies the real meaning of the whole story: America wants Serbia to carry that lithium west, not toward China.

The third reason is the military. According to the piece, Serbia is actively modernising its army with purchases from France, Spain, Germany and Israel. Forbes openly suggests the US should increase direct arms sales to bring Serbian forces closer to Western standards. In other words, buy from us, not just from the others.

The fourth reason is the Middle East. Serbia is described as a reliable ally of Israel and the United Arab Emirates, and the Israeli defence company Elbit Systems is building a drone factory worth around two billion dollars.

The conclusion from Forbes is that Serbia is a serious ally that delivers concrete results, unlike some other European partners. It sounds like a compliment. But compliments from great powers rarely come for free. The Balkans know this scene by heart: first the praise, then the bill. The question Belgrade should ask itself is not how valued it is, but what will be demanded in return.