Whether you are elected, appointed, or seize power, the fundamental problem of being a leader is what, if anything, you should do. This is true whether you lead a local club or a great nation. Generally speaking, the point of being a leader is to "improve" some metric, whether that be the lives of the people you lead or your bank account. So, leaders set out on "agendas," a list of projects and programs that hopefully will improve the relevant metric.
However, true leadership is often revealed not through the leader's agenda but when outside events intrude into the leader's agenda. One of the best recent examples is President George W. Bush, whose presidency was defined by 9/11 and the subsequent "war on terror." Now, world events have come to the Francis papacy.
The War on Ukraine is universally acknowledged as an inflection point for the world. Unlike the regional conflicts and more minor military actions that pervade recent history, this war has a greater potential to "go sideways" than any other military confrontation, probably since the Cuban Missile Crisis. Now, more than ever, careful, intelligent, and wise leadership is needed.
This conflict is also different in another fundamental way. This is Christians fighting Christians. That's not to say other conflicts weren't important and tragic (of course they are). However, it's unlikely that the leaders of the Taliban or Boko Haram, etc., were going to consider the opinions of a Pope. In the Ukraine conflict, Christian leaders, especially bishops, can potentially have an outsized influence on this war.
Vladimir Putin is presumably a Christian. He is Russian Orthodox. Pope Francis should fly immediately to Moscow. Not a big diplomatic mission with a well protocoled prepared agenda. He should get on his plane and go. Will Russia let him in? Probably. If not, they will fall under greater condemnation. The Pope has already broken protocol by condemning the invasion. Moreover, he has broken diplomatic protocol by spontaneously visiting the Russian embassy in Rome to convey his concerns. Thus, an unscheduled trip that may irritate the Russians is a logical step in the Pope's actions.
The Pope should visit the Catholic Bishop of Moscow and immediately consecrate Russia BY NAME to the Immaculate Heart of Mary. There are tons of videos and articles online debating whether the consecration has ever been properly accomplished, so that issue is not for this piece. First, there is no harm in doing it again. Second, on Ash Wednesday, the Bishops of Ukraine sent a letter explicitly asking the Pope to concentrate Russia and Ukraine to the Immaculate Heart. Third, Putin himself has previously asked for it (or at least about it). So, whether it has ever been done before, do it again explicitly and end any lingering doubt.
Then Pope Francis should reach out to the Russian Orthodox bishop. Together, they should process the Blessed Sacrament through the streets of Moscow to the Kremlin. Let the Orthodox lead; this is not about credit. Then, at the Kremlin, they should pray the Rosary. How many thousands of Muscovites would come out for that? Then they should ask to meet with Putin.
Will Putin accept? Probably. Again, if he says no, he looks terrible, really terrible – because he has held himself out as a Christian. If he does meet with them, they don't have to tell him he's wrong. Just having the meeting will give Putin the exit ramp he needs. Ask him, "what realistic concessions do you need to save face enough to stop?"
Then Pope Francis should fly immediately to Kyiv. He should publicly announce this and tell Vladimir Putin he is doing this. If Putin had chosen not to meet with him, the Pope should announce exactly when his plane leaves and when he will arrive in Kyiv. Would Putin allow his forces to potentially kill a sitting Pope? Not likely. Russia has already agreed to humanitarian cease-fires. They would likely grant another temporary cease-fire to accommodate the Pope.
In Ukraine, the Pope should repeat the process. Together with the Ukrainian bishops (Orthodox and Eastern Rite Catholic), they should process the Blessed Sacrament through the streets and consecrate Ukraine to the Immaculate Heart of Mary. If possible, Pope Francis should meet with Zelenskyy. This would probably be more difficult than meeting with Putin because Zelenskyy is in hiding. Arranging a meeting at a location that it would be safe for Zelenskyy to meet and then going back to his secure location without revealing it would be the tricky part. The Pope's mere presence in Kyiv would further pressure Russia to turn back. If Putin didn't offer a truce before, he may at this point.
Now, I'm not naïve. I know this is unlikely to happen. People will say that even a Pope can't fly into Moscow and meet with Putin. Even if he can get in, he can't hold massive rallies without permission and logistics. People will say a Pope can't go into a war zone; obviously, he could be killed. All true, but regular leaders are not the Pope. Regular leaders don't have authority from God. Would the Pope's life be at risk? Probably to some degree, and Popes, like everyone else, have a natural instinct to say alive, but unlike regular leaders, that shouldn't be the sole, or even the main, criteria governing their actions.
Imagine what a Pope taking action like this would do for the world? Above and beyond the lives it might save, the souls that would be enlivened would be uncountable. The case against war would be burned into the heart of the world. Respect for religion would be renewed. Pope Francis, who speaks about getting the smell of the sheep on you, would set an example that would change the course of history.