When President-elect Volodymyr Zelenskiy enters office as Ukraine’s sixth president by June 3, he will have a full in-tray waiting for him. The most pressing matter will be Russia and its ongoing war in the Donbas. Russian President Vladimir Putin has already set the new Ukrainian leader his first test — how to respond to the Kremlin’s decision to start issuing Russian passports to Ukrainians in the Russian-occupied parts of the Donbas.

It’s no coincidence that Putin chose to put his “passportization” scheme, in preparation for at least two years already, into motion just days after Zelenskiy’s election. Make no mistake: this is a direct challenge to Ukraine’s sovereignty, and Putin is not only testing the reaction of Ukraine’s new leader, but the responses of Ukraine’s friends and allies. If there is no strong answer to this outrage, such as an increase in Western sanctions, the Russian dictator will judge it safe to turn up the pressure.

Moscow hopes that Zelenskiy will cut a deal: It wants Ukraine to accept back the occupied territories, but for them to have a large measure of autonomy (read “Kremlin influence”) so that Ukraine remains weak and unstable. It also wants Ukraine to accept the loss of Crimea, and will offer a cheap gas deal as a sweetener, but also as a way to continue to poison Ukraine with corruption. The pro-Russian politician Viktor Medvedchuk hinted at the possibility of such a deal even before Zelenskiy’s election.

It is essential that Zelenskiy does not yield: Many will see it as a betrayal of national interests if he does. While Zelenskiy’s supporters want change, they do not want Ukraine to change back to being dominated by Russia.

Zelenskiy’s response to this challenge, and the controversy over Ukraine’s new language law, will set the tone of his presidency for the months and years to come. Let’s hope he gets it right.