Eyeing 2012 polls
With Mexico's left divided and Calderon sinking in opinion polls, the PRI is eyeing a return to national power in 2012, two terms after PAN ended its 71-year rule in 2000.
Al Jazeera's Franc Contreras, reporting from Mexico City, said people were already talking about the possibility of a 2012 election.
"Last year in mid-term elections the PRI took control of the lower house of congress once again," he said.
"Mexicans have not had faith in the right-leaning party that is currently in power here, and they are talking about the devil they know returning to power."
Al Jazeera's Mariana Sanchez, reporting from Cuidad Juarez, said there were mixed feelings regarding Sunday's election.
|Turnout was low in some areas plagued by drug violence [Reuters]
"There was some voter apathy, but some also felt it was their duty to vote and believe change can be brought about. However, many here also do not trust politicians, considering the security situation has been so bad," she said.
"The governors in many parts of Mexico run their states like fiefdoms, but after this election, we may see them working closely with President Felipe Calderon in light of the deteriorating security situation and the fact that some drug cartels are gaining further ground.
"I think they now know they can no longer work autonomously," our correspondent said.
Campaigning was blighted by drug gang intimidation in northern states as suspected cartel hitmen murdered two candidates and threatened others in recent weeks.
|Tom Ackerman reports on how local elections are a major test of public support for Calderon
It was some of the most blatant evidence of traffickers interfering in politics since Calderon came to power in late 2006 and launched a drug gang crackdown that has left more than 26,000 people dead, mostly from drug gangs and the police, but also civilian bystanders.
There were no reports of drug-related violence around polling stations on Sunday, but some voters reported vote buying and irregularities in several states on a tense election day.
In the northeastern state of Tamaulipas, plagued by drug gangs, long lines formed at polling stations after some 40 per cent of election volunteers quit fearing attacks.
And in terrorised towns outside Ciudad Juarez, which feuding cartels have turned into one of the world's deadliest cities, only around 20 per cent of voters turned out.