The third caliph, Uthman, solved this political problem by choosing one of these collections to be the standard version for the entire Muslim community. He had the other collections destroyed.
Sahih Bukhari 6.510:
Narrated Anas bin Malik: Hudhaifa bin Al−Yaman came to `Uthman at the time when the people of Sham and the people of Iraq were Waging war to conquer Arminya and Adharbijan. Hudhaifa was afraid of their (the people of Sham and Iraq) differences in the recitation of the Qur'an, so he said to `Uthman, "O chief of the Believers! Save this nation before they differ about the Book (Qur'an) as Jews and the Christians did before." So `Uthman sent a message to Hafsa saying, "Send us the manuscripts of the Qur'an so that we may compile the Qur'anic materials in perfect copies and return the manuscripts to you." Hafsa sent it to `Uthman. `Uthman then ordered Zaid bin Thabit, `Abdullah bin AzZubair, Sa`id bin Al−As and `AbdurRahman bin Harith bin Hisham to rewrite the manuscripts in perfect copies. `Uthman said to the three Quraishi men, "In case you disagree with Zaid bin Thabit on any point in the Qur'an, then write it in the dialect of Quraish, the Qur'an was revealed in their tongue." They did so, and when they had written many copies, `Uthman returned the original manuscripts to Hafsa. `Uthman sent to every Muslim province one copy of what they had copied, and ordered that all the other Qur'anic materials, whether written in fragmentary manuscripts or whole copies, be burnt. Sa`id bin Thabit added, "A Verse from Surat Ahzab was missed by me when we copied the Qur'an and I used to hear Allah's Apostle reciting it. So we searched for it and found it with Khuza`ima bin Thabit Al−Ansari. (That Verse was): 'Among the Believers are men who have been true in their covenant with Allah.' (3 3.23)