The lesson of the Apple/Ireland case is that taxing digital businesses under the existing rules is really, really hard.

Here's why:

The Commission claimed that Apple should have paid Irish tax on all its worldwide profits.

But Apple didn't do remotely enough in Ireland to justify this. Irish tax wasn't being avoided.

What about all the countries where Apple actually makes its money? The places where people buy/download stuff? UK, France, Germany etc etc?

But tax isn't charged on a destination basis - so UK, French, German tax wasn't being avoided.

What about the US? That's where the value is ultimately generated.

But (gross simplification alert) the US has been generally cool with its multinationals paying little/no US tax on their worldwide profits.

So US tax wasn't being avoided either.

All of which means that it's really really hard to find ways of getting digital MNEs to pay materially more tax under the existing frameworks.

You want them to pay more tax? You have to change the rules. And you have to find a way of doing this that the US can't block.

Which means not Pillar One and Pillar Two. And not unitary tax. Something more radical.