Support for Ukraine remains high across the European Union, but authors of the study say politicians should focus on defining an acceptable peace.
Only one in ten Europeans believe that Ukraine can defeat Russia, according to an EU-wide poll.
Conducted across 12 EU countries - including France, Germany, Hungary, Italy, the Netherlands, Poland, Spain and Sweden - the survey found that pessimism about the war's outcome was being fuelled by Ukraine's failed counteroffensive, a potential US policy shift and the possibility of Donald Trump getting into the White House.
The report - titled 'Wars and Elections: How European leaders can maintain public support for Ukraine' - found that 20% predicted a Russian victory.
The findings come on the eve of the second anniversary of Russia's full-scale invasion of Ukraine on 24 February 2022.
Though support for Kyiv among Europeans remains high, some form of "compromise settlement" is seen by those polled as the most likely solution to the war.
This marks a shift in sentiment, with a majority of Europeans saying Ukraine must regain all of its lost territory this time last year.