Very few people would question the rightness of Wikipedia but even it has problems.

For example the rhetoric may change depending on the language:

• Присоединение Крыма к Российской Федерации (Accession)
• Annexation of Crimea by the Russian Federation (Annexation)

Or intended vandalism:

• List of hoaxes on Wikipedia

By the way in the Wikipedia itself there is an article about this question

• Reliability of Wikipedia

So I wouldn't recomend to think that Wikipedia is always right and you should not debate if all your information is from Wikipedia while your opponent has information on the subject of the dispute from other sources.