Militarily, there is no question that Ukraine needs heavy weaponry to continue to withstand Russian aggression.
Mariupol shows that the success of the battle for Kyiv cannot be repeated everywhere.
Politically, however, things are not quite as simple as some foreign politicians in Germany, both experienced and latecomers, might think.
Russia has threatened a response, even detailing which weapons systems the West should not supply.
You can't just ignore that, it requires at least a vote in NATO.
In the worst case, the consequences of Russian retaliation would have to be borne by all allies.
It is debatable whether the West is too impressed by Putin's threatening gestures.
His army is stuck in Ukraine, and a westward spread of the war is likely to overwhelm him.
But even if one takes this risk seriously, the arms deliveries can be used as leverage against Russia.
If Putin does not want to see heavy weapons from the West in Ukraine, then concessions should be demanded from him: a ceasefire, for example, and talks about a withdrawal.
If the West, especially Washington, really wants Putin not to win this war, then such levers must be used now.