EMBATTLED Chief Justice Renato Corona faces uncertainty right in his own backyard.

Sources bared that Supreme Court Associate Justice Antonio Carpio -- Corona's professional rival and said to be Malacañang's pick to replace the Chief Justice -- will be the ponente (writer) of the decision on petitions challenging the legality of the impeachment.

Towards the end of the Arroyo administration Corona and Carpio were the top nominees to the then vacant chief justice position but the latter opted to withdraw from the race believing that then President Gloria Macapagal-Arroyo is devoid of authority to appoint the successor of Chief Justice Reynato Puno because of the election ban on appointments.

However, the SC ruled that Arroyo could appoint the new chief justice which eventually was Corona.

Sources said one of the four petitions questioning the legality of Corona's impeachment case will go to Carpio after the high court held a raffle just recently.

The four separate cases filed in court are the cases filed by petitioners Danilo Lihaylihay, crusading lawyer Vladimir Cabigao, former Integrated Bar of the Philippines President Vicente Millora and human rights lawyer Oliver Lozano.

These four cases were raffled off to different justices but the lowest docket number went to Carpio.

Under the Internal Rules of the high court, different petitions anchoring on the same legal grounds shall be consolidated and the ponente will be the magistrate who will get the lowest docket number.

The case of Lihaylihay is the one with the lowest docket number which went to Carpio.    

Once the case shall be consolidated, it will be handled by Carpio.

However, Court observers say that Corona will not benefit from this situation since Corona and Carpio are “mortal enemies.”

According to a SC justice, it is very unlikely for Carpio to draft a resolution for the issuance of a temporary restraining order (TRO) which would stop the Senate Impeachment Court from hearing the Corona impeachment case.

In the petition filed by Millora and Cabigao, they alleged that the filing of the complaint was done “in conspiracy” with President Benigno Aquino III.   

Millora urged the SC to declare null and void the articles of impeachment.  

He argued that the purpose of the complaint is to malign not only Corona but the whole high tribunal.