"Given the fact that the Europeans themselves are not united on this - for example, Kosovo has not been recognized by all EU member-states - it will, in my opinion, very clearly go in the direction of Russia effectively playing a very strong role there in the future, or having an influence," said Janssen, who is a lecturer at the Institute of Anglo-American history at the University of Cologne.
Speaking about the expansion of NATO in the region, Janssen said he was confident there would be none in the coming years.
"Trump will have no interest in that. To him, this is a second and third-rate issue, and without the United States... there will be no significant security and political progress there. The U.S. has always been an important part of NATO and if they now withdraw or partially withdraw, then the alliance, on the one hand, very clearly loses in importance, and on the other - all expansion is being called into question. And that, very clearly, is a success for (Russian President Vladimir) Putin," added the German political scientist.
He went on to say that there were "still more or less expressed, old nationalist regimes in the Balkans that have basically been in charge since the collapse of Yugoslavia."
"We have been very clearly reminded of this by the conflict a few days in Kosovo involving a Serbian train and on the other hand, the reaction of the Kosovo Albanians. There's also the situation in Bosnia-Herzegovina with the Serb Republic, and partially, also in Croatia. Until now, the West and the United States have always been saying: we want that conflict to end peacefully long-term, and to take care of the political balance in the true sense of the word. I'm afraid that now, with Putin, who has a very clear interest to strengthen the Serbs, and on the other hand with Trump, an imbalance is truly being created there once again, so the Serbs could eventually unilaterally sharpen the tone - to express myself cautiously," said Janssen.
He also thinks that "Pristina's fear of a partition of Kosovo" is "certainly justified."
"The Serbian president indirectly threatened them with war. The Kosovo leadership... has also reacted belligerently. Therefore, we see very little on both sides in favor of easing the tensions. I believe that this remains for both sides a very crucial issue. The Kosovo Albanians want the whole of Kosovo, and Serbs do not want to recognize Kosovo as an independent state, and want authority over at least the northern part. There's a lot of potential for conflict there," Janssen said.
Conflict, according to the German analyst, was prevented this time "by the fact there are international troops in Kosovo."
"But if they were to be withdrawn - which, of course, is always a possibility, for example, the U.S. could withdraw its contingent - then the question is whether the Europeans would have the will and whether they would be able to actually massively station troops there, which would then in the end prevent conflict. I spoke with many people in the Balkans, in Sarajevo, in Kosovo, and they all unanimously say that an armed conflict could break out in the next three to four years unless the West made an attempt to support democratic, civil society there. And at this time, with the isolationist tendencies of Donald Trump, I do not see it," he added.
Janssen said that, "in the mid-term," one can expect the withdrawal of U.S. troops from Kosovo, adding that he thinks this would be "a disastrous scenario for the Balkans and for the EU, because the Balkans would be left to itself."
"I believe that these countries, more than 20 years after the Dayton Agreement and 17-18 years after the Kosovo war, are not in a position to have civil-democratic structures and are not able to manage them autonomously. Therefore, the West must help there... And if all that fails, then, in my opinion, the situation is dark. For the EU, this will be a very big problem for the simple reason that I believe the EU, because of its own internal crisis, is unable to solve the issue of the Balkans alone and in a sovereign manner. It will be very difficult for the European Union," he said.
Speaking about the U.S. sanctions imposed on RS President Milorad Dodik, Janssen said he "can imagine the administration of Donald Trump lifting them."
"I can imagine it, given the fact that Russia condemns these sanctions, and that Trump will, at the very least not adhere to these sanctions, if he wants a deal with Putin. Namely, there are many ways - sanctions don't have to be lifted, they could simply not be implemented. That's also possible..." Jenssen said.