The possibility of Pedro Sánchez ending up investigated by the Supreme Court would open a political and judicial scenario of enormous impact: that of the suplicatorio (request for authorization) before the Congress of Deputies.
As a deputy, the President of the Government enjoys parliamentary immunity. This means that he cannot be charged or prosecuted without the prior authorization of the Lower House.
Therefore, if the Supreme Court found sufficient evidence to act criminally against Sánchez, it would have to request permission from Congress to continue the proceedings.
What is the suplicatorio
The suplicatorio is the mechanism by which the Supreme Court requests authorization from the corresponding Chamber to proceed against a deputy or senator.
In Sánchez's case, the request would have to be addressed to the Congress, which would have to process it through its internal bodies before submitting it to a vote in the Plenary session.
The political key is evident: the judicial future of the president would depend, at that point, on a parliamentary decision.
The role of the majority that supports the Government
The scenario opens a fundamental question: what would the PSOE and its partners do if the Supreme Court requested the suplicatorio to act against Sánchez.
The investiture bloc has so far supported the Government in the main votes of the legislature. If that majority were maintained, it could block the authorization or, at least, condition the political timing of the proceedings.
That point turns the suplicatorio into a legal procedure with direct political consequences, especially at a time of strong judicial pressure on the PSOE's environment.
The procedure in Congress
Once the suplicatorio is received, the Presidency of Congress, after agreement by the Board, must forward it to the Commission on the Status of Deputies.
That commission must hear the affected deputy and prepare a proposal. Then, the matter is submitted to the first ordinary Plenary session of the Chamber.
Congress must communicate its decision to the judicial authority. If it does not rule within the foreseen period, the suplicatorio is considered denied.
Sánchez, subject to the jurisdiction of the Supreme Court
The condition of President of the Government and deputy places Sánchez under the jurisdiction of the Supreme Court in a potential criminal case.
This prevents an ordinary judge from directly charging him. If, during an investigation, evidence against him were to appear, the investigating judge would have to submit a reasoned statement to the Supreme Court for the Second Chamber to decide whether to open proceedings.
Only at a later stage, if the procedure advanced towards a formal indictment or prosecution, would the request for leave come into play.
An uncomfortable precedent for La Moncloa
The debate comes in a particularly delicate context for the Government. Judicial investigations affecting the PSOE and its circle have increased pressure on La Moncloa and have forced Sánchez to appear in Congress to explain the political situation.
An eventual request for leave would not, in itself, imply a conviction or an immediate trial, but it would represent a qualitative leap in the Executive's political crisis.
Congress as the final filter
The final decision on whether to authorize the procedure would fall to the Plenary of Congress.
That point makes the Lower House the last institutional filter before the Supreme Court could proceed criminally against a deputy. In the case of a sitting Prime Minister, the political impact would be unprecedented.
A scenario of maximum tension
The hypothesis of an indictment of Sánchez before the Supreme Court combines three explosive elements: judicial pressure on the PSOE, the fragility of parliamentary majorities, and Congress's ability to block or allow the progress of a criminal case against the Prime Minister.
If the scenario were to materialize, the Government would not only face a judicial crisis but also a decisive test of parliamentary resilience.