On July 6, the Senate will convene as an impeachment court to try Vice President Sara Duterte. Much of the nation’s attention will understandably focus on the respondent. The questions dominating public discourse are familiar. Is the evidence sufficient? Will the prosecution prove its case? Will the defense dismantle the Articles of Impeachment? Will there be enough votes to convict or acquit?

These are important questions. They are not, however, the first questions the Senate must answer.

Before the first witness is called, before the first piece of evidence is offered, before the first objection is raised, every senator will stand, raise a hand, and take an oath.

That moment may last less than a minute.

It may also become the most important minute of the entire impeachment trial.

An oath is not an opening ceremony. It is the constitutional line separating politics from judgment. It is the moment when senators are asked to set aside the very instincts that brought them to power. They have spent their careers building coalitions, defending allies, attacking opponents, negotiating compromises, counting votes, and winning elections. Yet the Constitution asks them, in one solemn act, to become something else.

Judges.

Whether that transformation is possible will determine not only the fate of Vice President Duterte but also the credibility of the Senate itself.

That is the true weight of an oath.

An oath is a promise that one will judge not according to loyalty, popularity, political expediency, or personal preference, but according to the Constitution and the evidence presented. It is an affirmation that public office carries obligations higher than partisan affiliation. It is a declaration that constitutional duty will prevail over political convenience.

At least, that is what it is supposed to mean.

The challenge is that the impeachment trial does not begin in a political vacuum. It begins in an environment already saturated with public declarations, hardened positions, and partisan expectations. Long before the Senate convenes as an impeachment court, political camps have already declared victory. Supporters of the Vice President insist that the impeachment is nothing more than political persecution. Her critics argue that the evidence already justifies removal from office.

The trial has not yet begun, yet many have already reached a verdict.

This raises an uncomfortable but necessary question.

Can senators who have publicly defended the Vice President still persuade the public that they approach the trial with an open mind? Equally, can senators who have previously expressed strong views against her convince the nation that they will judge solely on the evidence presented in court?

The Constitution does not require senators to erase their political histories. That would be impossible. They are elected officials, not career magistrates. What it does require is something more demanding. It requires them to demonstrate that when they sit as impeachment judges, constitutional fidelity supersedes political identity.

The oath is the bridge between those two roles.

If that bridge collapses, the impeachment court risks becoming nothing more than a Senate session wearing judicial robes.

This is why the oath matters more than many people realize.

It is easy to view it as a ceremonial formality. It is far more than that. It is the moral foundation upon which the legitimacy of the entire proceeding rests. Every witness who testifies, every document admitted into evidence, every legal argument advanced by the prosecution and the defense derives its meaning from the assumption that those hearing the case are genuinely prepared to weigh it impartially.

If the outcome is perceived to have been predetermined, then the trial itself becomes little more than political theater. Evidence loses its purpose because conclusions have already been reached. The constitutional process becomes an elaborate performance designed not to discover the truth but to legitimize decisions made elsewhere.

That would be a profound injury not only to the respondent but to the institution of impeachment itself.

The Senate occupies a unique place in our constitutional architecture. No other institution is entrusted with the authority to remove the President, the Vice President, members of the Supreme Court, constitutional commissioners, and the Ombudsman through impeachment. It is among the gravest powers any democratic institution can exercise because it sits at the intersection of law and politics.

Precisely because impeachment is political in consequence, it must be disciplined by constitutional principles.

Otherwise, it degenerates into numbers alone.

The Filipino public has become accustomed to viewing impeachment through the lens of arithmetic. How many votes does the prosecution have? Who are the swing senators? Who might defect? Which political coalition has the advantage? These questions dominate headlines because they are tangible and measurable.

But they are not the questions history ultimately asks.

History asks whether institutions rose to the occasion entrusted to them.

The impeachment trial of Chief Justice Renato Corona continues to be debated not simply because of the verdict but because it became a defining test of the Senate’s role as an impeachment court. Regardless of one’s position on that case, it established a benchmark against which every subsequent impeachment proceeding would be measured.

The trial of Vice President Duterte will inevitably become another such benchmark.

The senators know this. Every vote they cast will outlive their terms in office. Future campaigns will revisit it. Future biographies will record it. Future students of constitutional law will study it. The public may eventually forget individual witnesses or specific exhibits, but it will remember whether senators appeared to honor the oath they swore before the trial began.

That is why constitutional courage matters.

There will be pressure from every direction. Political parties will exert influence. Allies will expect loyalty. Critics will demand accountability. Public opinion will shift with every revelation and every headline. The temptation to think first as politicians and only later as impeachment judges will be immense.

The oath exists precisely for moments like these.

Its purpose is not to eliminate politics. That would be unrealistic. Its purpose is to remind senators that there are moments when constitutional duty must take precedence over political calculation.

Whether they succeed is a question only time can answer.

On July 6, the country will watch senators raise their right hands and pronounce a solemn promise. The words themselves will take only seconds. Living up to them may require weeks of discipline, restraint, and courage.

Every impeachment begins with an oath.

Every democracy depends on whether that oath still means something.

On Monday, the nation will witness senators swear to administer impartial justice.

The impeachment of Vice President Sara Duterte begins with that oath.

The Senate’s judgment begins with whether Filipinos believe it.