• The Greek situation is escalating, banks will be closed, capital controls imposed, and Greece is likely to default on its debt to the IMF on Tuesday.
• This could leave a big bill to other eurozone countries and tip the already precarious public finances over the edge in several member states, most notably Portugal.
• Several countries are plagued with very high and rising debt to GDP ratios without being able to do much about this within the constraints of the eurozone.
• Despite the firepower of the ECB, these situations could very well become untenable sooner rather than later.

Source: Portugal, The Next Eurozone Domino? | Seeking Alpha