According to international law, the answer is no, at least not while they are in office.
The International Court of Justice has already ruled on this: Heads of State enjoy immunity from the jurisdiction of other countries. This means they cannot be arrested or prosecuted by them.
But let’s be clear: Immunity is not the same as impunity.
A Head of State is protected during their term so they can carry out their duties without outside interference. That’s why this immunity usually ends when they leave office, allowing them to face trial.
Now, as a general rule, their official acts remain immune continually. However, international law has evolved.
If a Head of State commits grave atrocities, such as crimes against humanity, they lose that protection for their official acts and can be prosecuted once they leave office.
But here is the most important part: these rules only apply between countries.
International Courts are a completely different story. They can prosecute leaders at any time.
In fact, the International Criminal Court has stated that if it issues an arrest warrant against a sitting Head of State, other obliged governments cannot refuse to arrest them on the basis of immunity. They must comply.
In short: A sitting President cannot be touched by another country’s government… unless the International Criminal Court orders the arrest.
References
International Court of Justice (ICJ): Arrest Warrant of 11 April 2000 (Democratic Republic of the Congo v. Belgium), Judgment, I.C.J. Reports 2002.
International Criminal Court (ICC): The Prosecutor v. Omar Hassan Ahmad Al-Bashir, Appeals Chamber Decision on Jordan’s Appeal against the Findings of Pre-Trial Chamber II, No. ICC-02/05-01/09 OA2, 6 May 2019.
International Law Commission (ILC): Draft articles on Immunity of State officials from foreign criminal jurisdiction, Report of the International Law Commission, 73rd Session (A/77/10), 2022.
Oxford Public International Law: Heads of State, Max Planck Encyclopedias of International Law [MPIL].
