Evo Morales' candidacy was unconstitutional
Bolivia has two-vote counting systems, one of which delivers a quick (but incomplete) result and the other provides a legally binding count and takes longer. The interruption of one of the counting systems and the discrepancy between the results obtained through both systems have raised questions over the validity of the electoral results and the possibility of electoral fraud.
The quick count (known as TREP) allows for the rapid and transparent transfer of electoral tally sheets. It requires the uploading of poll sheet photographs to a common database to calculate the vote count. During the electoral count, in the evening of October 20th, the transfer of results was interrupted, following orders from the body responsible for the elections. The count was stopped at a time when the results did not favor the 10-point lead required by the left-wing candidate, Evo Morales, to claim the presidency without requiring a second voting round. By the time the system was re-established, the results showed that Morales had reached the 10-point lead he needed.  There is no reason why the electoral count should have been stopped, and the sudden increase in votes to president Evo Morales has cast doubt over the validity of the results. This doubt was shared by international observers from the European Union (EU) and the Organization of American States (OAS).  In response to the irregularities and the popular unrest that followed the elections, the Bolivian government called for an independent investigation to be conducted by the OAS. The government agreed the findings of the investigation would be binding. On November 10th, the OAS published its preliminary report, which gave no legitimacy to the count provided by the government and established that there had been "a conflict of good practice in the electoral process and a lack of respect for safety standards, all of which render invalid the results of the election". 
According to the research conducted by the Center for Economic and Policy Research (CEPR), a Washington DC based think tank, it is not unusual that a quick count will find differing results from the more systematic, official count. More importantly, the results from the official count followed a very similar trend from those of the quick count, and the difference between the two is not dramatically large. The same research institution was able to conduct statistical analysis that proves the results fall in line with voting trends among smaller rural communities, which are last to be included in the count. The OAS's attack relies on the "interruption" of the count on election night, but this interruption only applied to the quick count. However, the binding, official count, was never stopped. The OAS, led by its US Ambassador, is defending the rights of the elite it represents.
1. There were irregularities in the electoral count that were highlighted by the leader of the opposition and international organizations. 2. An independent investigation carried out by Morales' government concluded that the election had not been conducted fairly. 3. The evidence shows that the electoral process was not conducted in a manner that guaranteed its results.
1. The evidence provided to support the argument of electoral fraud was only defended by large international institutions which support the same interests as the Bolivian elite, who opposed Morales. 2. The findings from these investigations are supported by vague arguments that lack data. 3. Research conducted by third parties supports the official vote count.