The European Union expects candidate countries to be democracies governed by the rule of law, notes the V-Dem Liberal Democracy Index:
Despite some temporary reversals, all countries generally made progress with regards to the rule of law and democracy from the 1980s until the mid-2000s; however, in more recent years, we can see sustained declines in Turkey as well as the former Yugoslav Republic of Macedonia.
For Albania, improvements in liberal democracy have been remarkable, with very low levels until 1990, strong increases during the 1990s, and stabilization since the beginning of the 2000s. For Montenegro on the other hand, the process has been slower and more gradual. Lastly, Serbia spent most of the 1990s as the country with the lowest score on the index, but experienced strong increases in the 2000s to the extent that it is currently ahead of all of its fellow candidate states.