“It’s a typical aftershock to have sovereign debt crises after banking crises. But Europe is extraordinary,” Rogoff said. “There’s all these political variables. I’d be shocked if they didn’t have sovereign debt crises.”

“It was nuts to let Greece and Portugal in (to the EU) as quickly as they did,” he added. “They just looked the other way and decided to let them in. Greece had high inflation, default risks. Portugal had an IMF program early as 1984."

- Watch Kenneth Rogoff interviewed on CNBC above.

"I think they should have let Portugal and Greece go" before doing the bailout -- not overnight -- but in an orderly fashion, Rogoff said.

The European Commission indicated that their expansionist plans will likely continue earlier this week.

Estonia, a country of 1.3 million people, is on course to adopt the euro in January 2011, subject to the approval of all 27 EU member states, 16 of which are in the euro zone.

Estonia's sovereign debt was at 7.2 percent of GDP in 2009, well below the euro-zone average of 60 percent.