MANILA, Philippines - Before the impeachment court could issue a single subpoena for Supreme Court justices, the high court  already took jurisdiction on whether or not a magistrate can testify and run the risk of stepping on the constitutionally-enshrined separation of powers.

ABS-CBNnews.com sources said the issue was first tackled last Tuesday, and a decision could be made at the full court meeting this week.

Sources said the high court could not just wait for subpoenas to be issued to their members and delve later on an issue that could put it at odds with the impeachment court.

They said the high court decided on the matter when the prosecution included in a list of witnesses several of its members.

The prosecution may finally present this week Article 3 of their complaint against Chief Justice Renato Corona.

The article alleges that Corona “committed culpable violations of the Constitution and betrayed the public trust by failing to meet and observe the stringent standards under Article VIII, section 7 (3) of the Constitution that provides that “[a] member of the judiciary must be a person of proven competence, integrity, probity, and independence.”

There, the prosecution would also want to focus on the SC’s supposed flip-flopping in a decision concerning the retrenchment of the flight attendants of the Philippine Airlines.

Based on its original witness list, the prosecution wanted several associate justices to “testify on the circumstances of the transfer of the FASAP case from one division to another.”

The prosecution also sought to have the impeachment court subpoena several records in the SC.

On Thursday, however, Senate President Juan Ponce Enrile gave the prosecution a mouthful on its move to ask for numerous subpoenas.

“You ask us to subpoena SC records, we have to observe the [co-equality] among the three branches of government,” he had said.

The plan to summon more than 100 witnesses, including journalists, was met with criticisms.

In his Facebook account, lawyer Ted Te earlier said: “Putting media practitioners as well as sitting Supreme Court Justices as possible witnesses is just simply horribly wrong. Not only does it leave the trial open to a challenge that it was, after all, the institution of the SC itself that is now being tried, it also opens a door that should, at the moment, remain closed.”

He said bringing justices to the court also weakens the institutions put up by the Constitution. He said the magistrates should collectively decline such a plan.

The prosecution had already said it would still trim down the number of witnesses.